Safe Work Method Statement

Plumbing Drainage SWMS

Comprehensive Australian WHS Compliant SWMS

Generate SWMS Now View Sample PDF

No credit card required • Instant access • 100% compliant in every Australian state

5 sec

Creation Time

100%

Compliant

2,000+

Companies

$3.6K

Fines Avoided

Avoid WHS penalties up to $3.6M—issue compliant SWMS to every crew before work starts.

Drainage installation represents one of the most fundamental and safety-critical aspects of plumbing work, involving the installation of sewerage, stormwater, and wastewater systems that protect public health and environmental quality. This SWMS provides comprehensive safety procedures for drainage work in Australian construction environments, addressing the significant hazards of trenching and excavation, working near underground services, connection to existing systems, and the specific risks associated with installing and testing gravity drainage and pressurised sewer systems.

Start Generating SWMS See How It Works

Unlimited drafts • Built-in WHS compliance • Works across every Australian state

Overview

What this SWMS covers

Plumbing drainage installation is a fundamental component of construction work, establishing the underground and above-ground infrastructure that safely conveys sewage, wastewater, and stormwater away from buildings and properties to public sewer systems, septic systems, or designated discharge points. Properly installed drainage systems are essential for public health, preventing contamination of soil and groundwater, protecting building foundations from water damage, and ensuring compliance with environmental regulations governing wastewater and stormwater management. The complexity and safety-critical nature of drainage work requires qualified, licensed plumbers working to precise specifications derived from hydraulic calculations, building codes, and Australian Standards including AS/NZS 3500.2 for sanitary plumbing and drainage, AS/NZS 3500.3 for stormwater drainage, and AS/NZS 2032 for installation of PVC pipe systems. Drainage installations involve multiple distinct phases beginning with comprehensive site assessment, service location, and excavation planning to identify underground services, assess soil conditions, determine required trench depths and grades, and establish safe excavation procedures. The excavation phase involves digging trenches to specified depths and widths using hand tools, mechanical excavators, or combination methods, implementing trench support or benching systems to prevent collapse, and establishing safe access and egress points for workers. Pipe installation follows with careful placement of drainage pipes in prepared trenches, establishing correct grades and falls to ensure proper flow (typically 1:40 to 1:100 depending on pipe diameter and application), jointing pipes using appropriate methods for the pipe material (solvent cementing for PVC, rubber ring joints for certain applications, or fusion welding for polyethylene), and installing junction boxes, inspection openings, and fittings at required locations. Connection of new drainage to existing systems represents a particularly hazardous phase requiring excavation around existing live services, careful breaking into existing drains while managing sewage exposure, installation of junctions or penetrations, and ensuring proper sealing to prevent leaks and infiltration. Following installation, the system must be thoroughly tested using water testing, air testing, or smoke testing to verify the integrity of all joints and connections before backfilling can commence. The final phase involves bedding and backfilling trenches with appropriate materials, compacting in layers to prevent settlement, and restoring surface finishes to match pre-existing conditions or as specified in project requirements. Drainage work encompasses multiple pipe materials and joining technologies each with specific installation requirements. PVC (polyvinyl chloride) pipe remains the most common drainage material for residential and commercial applications, joined using solvent cement for pressure applications or rubber ring push-fit joints for gravity drainage. Earthenware (clay) pipes, once dominant but now less common in new installations, are still encountered in renovation work and repairs, using collar joints or rubber ring joints. Concrete drainage pipes are specified for large diameter installations, heavy traffic areas, or high-load applications, joined using flexible rubber ring joints or rigid cement mortar joints depending on design requirements. Polyethylene pipes are increasingly used for pressure sewer systems, stormwater, and specialised applications, with joining via electrofusion, butt welding, or mechanical compression fittings. Cast iron drainage, traditionally used for internal drainage stacks and underground building drains, utilises rubber coupling systems or traditional lead and oakum joints in heritage applications. Each material and joining method requires specific skills, tools, and quality control procedures to achieve compliant, leak-free installations. Drainage systems must be designed and installed to accommodate various loading conditions including dead loads from soil above the pipe, live loads from traffic or equipment above the trench, and the pipe's own structural capacity to resist crushing and deformation. Pipe bedding and backfilling practices directly affect long-term performance, with specification of appropriate bedding materials (typically clean sand, graded aggregate, or cement-stabilised sand), compaction requirements, protection from sharp rocks or debris, and proper support to prevent point loading on pipes. Installation must also consider pipe movement due to thermal expansion and contraction, ground movement, and building settlement, with appropriate joints, expansion provisions, and flexible connections at building penetrations preventing stress concentrations that could cause joint separation or pipe fracture. The regulatory framework governing drainage installation is comprehensive and strictly enforced to protect public health and environmental quality. All drainage work must be performed by licensed plumbers holding appropriate plumbing and drainage licences issued by state and territory regulatory authorities. Work must comply with the National Construction Code (NCC) Plumbing Code of Australia, which references Australian Standards and provides mandatory requirements for drainage design, materials, installation, testing, and documentation. Local water authorities and councils enforce additional requirements through technical standards, approval processes, and inspection regimes. Environmental regulations govern wastewater discharge quality, stormwater management, erosion and sediment control during construction, and protection of waterways from pollution. Occupational health and safety legislation mandates comprehensive risk management including Safe Work Method Statements for high-risk activities such as excavation deeper than 1.5 metres, working near underground services, and confined space entry for connection to existing systems.

Create Custom SWMS Download Template

Fully editable, audit-ready, and aligned to Australian WHS standards.

Why this SWMS matters

Drainage installation work presents some of the most serious and frequently encountered hazards in the plumbing trade, making comprehensive safety planning and implementation of appropriate control measures absolutely essential for protecting workers and ensuring regulatory compliance. The primary hazard—trench and excavation collapse—has caused numerous fatalities in the Australian construction industry, with workers buried under tonnes of soil in incidents that often occur with little or no warning. Ground can collapse suddenly when excavations exceed 1.5 metres depth without appropriate shoring, benching, or battering, when vibration from nearby equipment or traffic destabilises trench walls, when water infiltration saturates and weakens soil, or when excavations undermine adjacent structures or services. The consequences are catastrophic, with buried workers suffering asphyxiation within minutes as the weight of soil prevents chest expansion and breathing. Rescue is extremely difficult and time-critical, requiring specialised equipment and techniques often unavailable at typical construction sites within the brief window before asphyxiation occurs. Striking underground services during excavation presents equally serious risks including electrocution from damage to underground electrical cables, gas explosions from rupture of gas mains, flooding from water main damage, disruption to telecommunications services, and potential for explosion or toxic exposure from damaged chemical or industrial pipelines. Despite the availability of service location technologies and mandatory Dial Before You Dig notifications, service strikes remain common due to inaccurate service records, failure to use appropriate location methods, reliance on plans without physical verification, or inadequate supervision of excavator operators. Electrical cable strikes can result in fatal electrocution of machinery operators or workers in contact with excavation equipment, particularly in wet conditions where water provides a conductive path to ground. Gas main damage can result in immediate explosion if ignition sources are present, or catastrophic explosion hours later as leaked gas accumulates in confined spaces and is ignited by a spark or flame from distant sources. Sewage exposure during drainage work, particularly when connecting to existing systems or repairing failed drains, introduces serious biological hazards. Sewage contains pathogenic bacteria, viruses, and parasites that cause diseases including leptospirosis (Weil's disease), hepatitis A and B, gastroenteritis from various organisms, tetanus, and parasitic infections. Workers contract these diseases through direct contact with contaminated surfaces, inhalation of aerosols generated during drain cutting or high-pressure cleaning, ingestion via hand-to-mouth contact when eating without proper hand washing, and contamination of cuts and abrasions providing direct entry into the bloodstream. Leptospirosis is particularly dangerous, caused by bacteria from rat urine in sewage, and can result in severe illness with kidney failure, liver damage, respiratory distress, and potentially fatal outcomes if not promptly diagnosed and treated. The disease has a delayed onset with flu-like symptoms appearing 7-14 days after exposure, making the connection to sewage exposure easy to miss unless workers and medical practitioners are aware of the risk. Manual handling injuries are endemic in drainage work due to the heavy, awkward nature of pipes, fittings, and materials that must be manoeuvred into position in confined trenches with restricted working positions. PVC drainage pipes in 100mm to 225mm diameters and 6-metre lengths weigh 10-60kg and are unwieldy to handle even with multiple workers. Concrete pipes are substantially heavier, with 150mm concrete pipe weighing approximately 100kg per metre and larger diameters proportionally more. Workers suffer acute back injuries from lifting or lowering pipes into trenches, chronic musculoskeletal disorders from repetitive handling and awkward postures, and crush injuries from dropped pipes or materials. The confined trench environment compounds these risks as workers cannot adopt optimal lifting postures, escape routes are limited if loads shift or slip, and the edge of the excavation provides an unstable footing increasing the likelihood of slips and falls while carrying loads. The legal and financial consequences of safety failures in drainage work are severe. Trench collapse fatalities invariably result in WorkSafe investigation, coronial inquiries, and prosecution of the plumbing contractor and responsible individuals under WHS legislation. Recent prosecutions following trenching deaths have resulted in fines exceeding $1 million for companies and $300,000 for individuals, along with court-ordered safety improvements, adverse publicity, and potential director disqualification. Service strike incidents, even without injuries, result in substantial costs including emergency service attendance, service authority repair charges, business interruption claims from affected customers, and potential prosecution for failure to comply with service location requirements. Sewage exposure incidents leading to serious disease trigger workers' compensation claims, investigation of hygiene and PPE practices, and potential liability for long-term health impacts. Insurance implications include premium increases following claims, policy exclusions for future trenching or excavation work if safety systems are deemed inadequate, and potential for policy voidance if work practices materially breach policy requirements regarding high-risk activities. Implementing comprehensive SWMS for drainage installation provides multiple benefits extending well beyond minimum regulatory compliance. Documented safety procedures reduce incident rates by providing clear, specific guidance for hazard identification and control across all drainage work phases. The SWMS establishes systematic processes for service location verification, excavation planning, trench support selection and installation, and connection procedures that prevent the most common serious incidents. For plumbing businesses, robust drainage safety documentation demonstrates due diligence to regulators, strengthens tender applications particularly for government and commercial projects with rigorous contractor prequalification, and satisfies principal contractor safety requirements on construction sites. The SWMS supports effective worker training and induction by providing a structured framework for explaining hazards and safe work procedures to apprentices and less experienced plumbers. Regular SWMS review and updates incorporating lessons learned from near-misses and incidents drives continuous safety improvement. Most importantly, comprehensive drainage safety systems protect the lives and health of plumbers and labourers performing this hazardous but essential work, preventing tragedies that devastate families, traumatise co-workers, and damage businesses through prosecution, compensation claims, and reputational harm.

Reinforce licensing, insurance, and regulator expectations for Plumbing Drainage crews before they mobilise.

Hazard identification

Surface the critical risks tied to this work scope and communicate them to every worker.

Risk register

Trench and Excavation Collapse

high

Trench collapse during drainage installation represents the most catastrophic hazard plumbers face, capable of burying workers under tonnes of soil within seconds with often-fatal consequences. Collapse can occur when excavations exceed 1.5 metres depth without appropriate support systems including shoring boxes, trench sheets with bracing, or benching/battering of trench walls to stable angles. Contributing factors include soil type and condition with sandy or gravelly soils less stable than clay, water infiltration from rain, groundwater, or damaged water services saturating soil and reducing shear strength, vibration from nearby equipment, traffic, or machinery operation destabilising trench walls, proximity to structures with foundations potentially undermining stability, changes in soil layers within the excavation with some strata less stable than others, and extended duration of open excavations allowing progressive deterioration of unsupported walls. Workers in collapsed trenches are buried under soil weighing approximately 1.8 tonnes per cubic metre, preventing breathing and causing asphyxiation typically within 3-5 minutes. Rescue is extremely difficult requiring specialised equipment and training, with survival dependent on immediate response rarely achievable at typical construction sites. Additional injuries from collapse include crush injuries to extremities, fractures, and trauma from falling materials and equipment displaced by the collapse.

Consequence: Burial and asphyxiation leading to death, traumatic crush injuries, fractures, permanent disability, or serious injury requiring immediate emergency response and extended medical treatment

Underground Service Strikes

high

Striking underground services during drainage excavation poses extreme risks including electrocution from electrical cable damage, explosions from gas main rupture, and flooding from water service damage. Underground services are not always accurately located by existing plans and records, particularly in older urban areas where infrastructure has been modified over decades without consistent documentation. Service location failures occur when plumbers rely solely on service plans without physical verification, when services have been installed outside standard locations, when non-conductive services like plastic gas and water pipes cannot be detected by electromagnetic location equipment, or when inadequate clearances are maintained during excavation. Electrical cable strikes can result in immediate electrocution particularly in wet conditions where excavators and workers provide conductive paths to ground, with high-voltage cables capable of causing fatal injuries at several metres distance through ground gradients. Gas main damage releases flammable natural gas or LPG that can accumulate in excavations, trenches, and nearby structures, with explosion risk from any ignition source including electrical equipment, vehicle engines, or static discharge. Water main damage causes immediate flooding of excavations creating drowning risks for workers in trenches and undermining excavation stability potentially triggering collapse.

Consequence: Electrocution causing cardiac arrest and death, burns from electrical arcing, gas explosion causing traumatic injuries and fatalities, flooding and drowning, or environmental damage and massive service disruption affecting communities

Sewage and Wastewater Exposure

high

Drainage work, particularly when connecting to existing sewerage systems or repairing failed drains, exposes workers to sewage and wastewater containing pathogenic bacteria, viruses, parasites, and toxic chemicals. Exposure occurs during cutting into existing drains, clearing blockages, working in manholes and inspection pits, and handling contaminated soil from excavations around leaking drains. Diseases transmitted through sewage exposure include leptospirosis (Weil's disease) from bacteria in rat urine with symptoms including fever, severe headache, muscle pain, kidney and liver damage, and potentially fatal outcomes, hepatitis A and B causing liver inflammation and long-term health impacts, gastroenteritis from numerous bacterial and viral pathogens causing severe diarrhea and dehydration, tetanus from Clostridium bacteria in soil contaminated with sewage, and various parasitic infections. Transmission routes include direct skin contact with contaminated surfaces and liquids, inhalation of aerosols generated when cutting drains or using high-pressure cleaning equipment, ingestion through hand-to-mouth contact when eating or smoking without adequate hand washing, and contamination of cuts, abrasions, or existing wounds providing direct entry to bloodstream. Chemical exposure also occurs from industrial and commercial wastewater containing solvents, heavy metals, acids, and other hazardous substances discharged to sewer systems.

Consequence: Leptospirosis causing severe illness, organ failure, or death, hepatitis infection with chronic liver disease, gastroenteritis and serious dehydration, septicemia from infected wounds, parasitic infections, or chemical poisoning from toxic wastewater

Manual Handling and Musculoskeletal Injuries

medium

Drainage installation involves extensive manual handling of heavy, awkward materials including pipes, fittings, junction boxes, bedding materials, and backfill, with much of this work performed in confined trenches with poor working positions and restricted space. PVC drainage pipes in common 100mm to 225mm diameters and standard 6-metre lengths weigh from approximately 10kg to 60kg and are unwieldy due to their length and rigidity. Concrete pipes are substantially heavier with 150mm diameter pipe weighing approximately 100kg per metre, and 225mm pipe around 220kg per metre, requiring mechanical lifting or multiple workers. Workers must lower these materials into trenches, manoeuvre them into position while achieving correct grades and alignments, and connect pipes in awkward postures including bending, kneeling, and working in cramped spaces. The trench environment provides unstable footing with loose soil, limited space to position body appropriately for lifting, and restricted egress if loads shift or slip. Repetitive tasks including cutting pipes, preparing joints, and backfilling contribute to cumulative musculoskeletal strain. Additional hazards include crush and impact injuries from dropped pipes or materials falling into excavations, and acute injuries when workers lose balance or footing while carrying loads near trench edges.

Consequence: Acute back injuries requiring extended time off work, chronic musculoskeletal disorders affecting spine, shoulders, and knees, crush injuries to feet and hands from dropped materials, or falls into excavations while carrying loads

Confined Space Entry in Manholes and Inspection Pits

high

Connecting drainage to existing sewerage systems frequently requires workers to enter manholes, inspection pits, and pump stations classified as confined spaces presenting multiple serious hazards. These enclosed structures have limited entry and exit points complicating emergency egress and rescue, inadequate natural ventilation allowing accumulation of toxic or flammable gases, potential for oxygen deficiency from displacement by sewer gases, and risk of engulfment from unexpected inflow of sewage. Sewer gases include hydrogen sulfide (H2S) which is highly toxic with exposures above 100ppm immediately dangerous to life and health, causing respiratory paralysis and rapid unconsciousness, methane which is flammable and can create explosive atmospheres at 5-15% concentration, and carbon monoxide from industrial discharges or decomposition processes. Workers entering without atmospheric testing, ventilation, standby personnel, and emergency rescue provisions risk asphyxiation, toxic gas poisoning, or explosion. The confined space environment also exacerbates manual handling risks, restricts movement complicating work tasks, and creates psychological stress from claustrophobia and awareness of hazards. Engulfment hazards exist from unexpected discharge of sewage from upstream sources, rainfall entering storm systems, or pump station activation flooding the confined space and potentially drowning workers before they can exit.

Consequence: Asphyxiation in oxygen-deficient atmosphere, hydrogen sulfide poisoning causing unconsciousness and death, methane explosion with traumatic injuries, drowning from engulfment, or inability to escape during emergencies

Control measures

Deploy layered controls aligned to the hierarchy of hazard management.

Implementation guide

Comprehensive Service Location and Excavation Planning

Elimination

Eliminate or minimise underground service strike risks through comprehensive service location, verification, and excavation planning before any ground disturbance commences. Begin with mandatory Dial Before You Dig enquiry at least two business days before excavation, obtaining service plans for electrical, gas, water, telecommunications, and any other underground infrastructure. Recognise that service plans indicate approximate locations based on historical records which may be incomplete, inaccurate, or outdated, particularly in older urban areas. Supplement plans with physical service location using electromagnetic cable locators for metallic services and ground penetrating radar for non-metallic services including plastic gas and water pipes. Mark located services on ground surface using colour-coded paint or markers following Australian standards: red for electrical, yellow for gas, blue for water, orange for telecommunications, white for proposed excavation limits. Where services are indicated but cannot be physically located, implement hand digging or vacuum excavation to physically expose and verify service location, depth, and condition before proceeding with mechanical excavation. Establish exclusion zones around located services with minimum clearances—typically 300mm for hand digging near services and 500mm for mechanical excavation. Brief excavator operators on service locations, required clearances, and procedures for working near services. Implement permit-to-dig system for critical areas requiring supervisor authorisation before excavation commences.

Implementation

1. Submit Dial Before You Dig enquiry minimum two business days before planned excavation, providing accurate location details and proposed excavation extent 2. Review all service plans received, identifying electrical, gas, water, telecommunications, and any other services shown within or near the proposed excavation area 3. Conduct physical service location using electromagnetic locators and ground penetrating radar, systematically covering the entire excavation area 4. Mark all located services on ground surface using colour-coded spray paint or pegs, including service type and estimated depth 5. Where services are indicated by plans but not physically located, implement hand digging or vacuum excavation to expose and verify actual location 6. Establish and mark exclusion zones around all services with minimum clearances of 300mm for hand excavation and 500mm for mechanical excavation 7. Brief excavator operators and all workers on service locations, required clearances, emergency procedures for service strikes, and authorised excavation methods 8. Implement permit-to-dig system for work near high-risk services such as high-voltage electrical cables or high-pressure gas mains 9. Maintain hand digging tools, vacuum excavation equipment, or other appropriate methods at work site for safe excavation immediately adjacent to services 10. Implement spotter system with worker observing excavation and monitoring clearances to services when mechanical excavation approaches located services

Trench Support and Excavation Safety Systems

Engineering

Implement comprehensive trench support systems eliminating collapse risks for all excavations deeper than 1.5 metres and any shallower excavations in unstable soils or near structures. Conduct geotechnical assessment identifying soil types, stability, water table depth, and appropriate support requirements. For excavations deeper than 1.5 metres, implement engineered trench support including manufactured trench boxes or shields providing full protection for workers, aluminium hydraulic shoring systems installed progressively as excavation proceeds, sheet piling with walers and struts for extended trenches or unstable ground, or benching and battering to stable angles appropriate for soil type (typically 45 degrees or flatter for most soil conditions). Never enter unsupported excavations deeper than 1.5 metres regardless of soil type or appearance—ground can collapse suddenly without warning even in apparently stable material. Provide safe access and egress for all excavations deeper than 2 metres using ladders, ramps, or stairways positioned to enable workers to exit within 5 metres travel distance. Implement edge protection including barriers at trench edges preventing falls into excavations and controlling placement of spoil, materials, and equipment. Establish exclusion zones preventing vehicles, plant, and stockpiled materials from approaching trench edges where loading could trigger collapse. Monitor excavations continuously throughout work period, checking for ground movement, water infiltration, or deteriorating conditions requiring additional controls.

Implementation

1. Assess soil conditions before excavation using test pits, geotechnical reports, or visual soil classification to determine stability and support requirements 2. Prepare excavation plan documenting trench dimensions, soil type, water table depth, proximity to structures and services, and specified support systems 3. Mobilise appropriate trench support equipment before excavation commences—trench boxes, hydraulic shores, or sheet piling as required 4. Excavate progressively, installing trench support as depth increases, never permitting workers to enter unsupported excavations deeper than 1.5 metres 5. Install trench boxes or shields ensuring complete coverage of excavation depth and width, with no gaps exposing workers to unsupported ground 6. For hydraulic shoring, install walers and struts at specified vertical spacing (typically every 1.2-1.5 metres) with adequate hydraulic pressure preventing ground movement 7. Provide ladders or other access equipment in excavations deeper than 2 metres, positioned so workers are never more than 5 metres from an exit point 8. Install edge protection barriers at trench edges preventing vehicles, equipment, and personnel from approaching within 1 metre of excavation 9. Position excavated spoil minimum 1 metre from trench edges preventing surcharge loading that could trigger collapse 10. Implement exclusion zones preventing vehicle and plant movement near trenches unless specifically authorised with appropriate controls 11. Monitor excavations continuously for signs of ground movement, water infiltration, or deteriorating conditions requiring additional support or evacuation 12. Brief all workers on excavation hazards, support systems, emergency procedures, and prohibition on entering unsupported excavations

Sewage Exposure Prevention and Hygiene Protocols

Engineering/Administrative/PPE

Implement comprehensive controls minimising sewage exposure during drainage work through engineering methods, work procedures, personal protective equipment, and medical surveillance. Engineer work to reduce contact including isolation and bypass of active sewage flows before cutting into existing drains, use of remote cutting and connection methods where practical, and thorough cleaning and decontamination of work areas. Establish strict hygiene protocols including provision of hand washing facilities with soap and running water at all drainage work sites, prohibition on eating, drinking, or smoking in contaminated areas or while wearing contaminated PPE, and requirements for thorough hand and forearm washing before meals and at end of shift. Provide appropriate PPE including waterproof gloves resistant to biological contamination (nitrile or neoprene), eye and face protection against splashes and aerosols, waterproof protective clothing or disposable coveralls for work in contaminated environments, and respiratory protection when aerosol generation is unavoidable during drain cutting or high-pressure cleaning. Implement medical surveillance including hepatitis A and B vaccination for all workers regularly exposed to sewage, tetanus vaccination maintained current, pre-employment health assessments establishing baseline health status, and protocols for immediate medical assessment following significant sewage exposures or development of symptoms suggesting sewage-related illness including fever, headache, muscle pain, or gastrointestinal symptoms.

Implementation

1. Plan drainage connection work to minimise sewage exposure including scheduling during low-flow periods and implementing bypass pumping to divert active flows 2. Establish designated clean and contaminated zones on work sites with clear separation preventing cross-contamination of tools, materials, and eating areas 3. Provide hand washing facilities with soap, running water, and paper towels at all drainage sites, positioned for access when exiting contaminated work areas 4. Install safety signage prohibiting eating, drinking, or smoking in contaminated areas and mandating hand washing before these activities 5. Supply appropriate PPE including waterproof gloves, face protection, protective clothing, and respiratory protection, ensuring sufficient quantities for task duration 6. Train workers on proper PPE donning and doffing procedures preventing self-contamination, and provide designated areas for PPE removal and disposal 7. Implement immediate first aid for contaminated cuts or wounds including thorough washing, antiseptic treatment, and covering with waterproof dressings 8. Establish medical surveillance program including hepatitis A and B vaccination series for all workers regularly exposed to sewage environments 9. Maintain current tetanus vaccination for all workers with boosters per medical guidelines 10. Provide worker education on sewage-related diseases, early symptom recognition, and requirement to report potential exposures and seek medical assessment 11. Establish procedures for medical evaluation following significant exposures including splashes to face or eyes, contamination of wounds, or ingestion 12. Maintain records of vaccinations, medical assessments, and exposure incidents supporting health surveillance and workers' compensation claims

Manual Handling and Material Management Controls

Engineering/Administrative

Implement engineering controls and work procedures minimising manual handling injuries during drainage installation. Utilise mechanical aids including excavators with lifting attachments for lowering pipes and heavy materials into trenches, vacuum lifters for handling large diameter pipes, trolleys and pipe rollers for moving pipes on level ground, and crane or telehandler support for concrete and other heavy drainage components. Plan work site layout minimising manual handling distances, with materials delivered close to installation points, stockpiled systematically to reduce double-handling, and positioned to enable mechanical placement into trenches. Implement team lifting protocols requiring two or more workers for pipes and materials exceeding individual lifting capacity (typically 25kg manual handling limit for repeated lifting tasks, 15kg for awkward or unstable loads). Provide appropriate tools including pipe cutting equipment eliminating need to manually handle full-length pipes, joining tools enabling work in ergonomic positions, and excavation aids such as shovels with extended handles reducing bending. Establish work procedures including regular task rotation reducing cumulative exposure to repetitive manual handling, scheduled breaks for physically demanding tasks, and pre-work stretching and warm-up routines preparing workers for physical tasks.

Implementation

1. Assess all drainage installation tasks for manual handling risks using systematic risk assessment tools identifying high-risk handling activities 2. Specify mechanical handling aids appropriate for pipe types and site conditions—excavator lifting attachments, vacuum lifters, trolleys, or cranes 3. Plan site layout positioning material deliveries close to installation points and minimising handling distances from delivery to trench 4. Establish stockpiling procedures arranging materials systematically to reduce double-handling and enable mechanical placement into excavations 5. Implement team lifting protocols clearly specifying which materials require two or more workers based on weight, size, and handling difficulty 6. Provide training on safe manual handling techniques covering proper lifting posture, team communication, and recognition of lifting limits 7. Supply appropriate tools including power pipe cutters, joining equipment, and ergonomic shovels reducing physical strain 8. Establish task rotation schedules varying work activities throughout shift to reduce cumulative exposure to repetitive tasks 9. Implement scheduled rest breaks during particularly demanding tasks such as hand excavation or repetitive pipe placement 10. Brief workers on manual handling risks specific to drainage work and requirement to request mechanical assistance or additional workers when tasks exceed safe capacity

Confined Space Entry Procedures for Manhole and Pit Access

Engineering/Administrative

Establish formal confined space entry procedures complying with AS 2865 for any drainage work requiring entry to manholes, inspection pits, pump stations, or other enclosed structures. Classify each confined space and conduct risk assessment documenting specific hazards including toxic or flammable gases, oxygen deficiency, engulfment risks, and restricted access/egress. Implement permit-to-work system requiring written authorisation before any confined space entry, with permit documenting atmospheric testing results, ventilation arrangements, standby person assignment, emergency procedures, and expiry time. Conduct atmospheric testing before entry measuring oxygen concentration (must be 19.5-23.5%), flammable gases (must be below 5% LEL), hydrogen sulfide (must be below 10ppm), carbon monoxide (must be below 30ppm), and any other contaminants specific to the environment. Install forced-air ventilation using explosion-proof fans and ducting maintaining positive air exchange throughout entry period. Establish standby person system requiring trained worker stationed outside confined space maintaining continuous communication with entrant, monitoring atmospheric conditions, and prepared to initiate emergency rescue without entering the space. Provide retrieval equipment including full-body harness and tripod rescue system for vertical-entry confined spaces enabling non-entry rescue. Develop and rehearse emergency rescue procedures including coordination with emergency services familiar with confined space rescue.

Implementation

1. Identify all confined spaces requiring entry for drainage work including manholes, inspection pits, pump stations, and any other enclosed structures 2. Conduct risk assessment for each confined space documenting specific hazards, atmospheric testing requirements, and control measures needed 3. Develop written confined space entry procedures specific to drainage work covering atmospheric testing, ventilation, communication, and emergency response 4. Implement permit-to-work system requiring completed, authorised entry permit before any confined space access 5. Conduct pre-entry atmospheric testing for oxygen, flammable gases, hydrogen sulfide, and carbon monoxide using calibrated, certified instruments 6. Install forced-air ventilation providing minimum 6 air changes per hour, with intake positioned away from contamination sources 7. Establish continuous atmospheric monitoring throughout entry period with audible alarms alerting to dangerous conditions 8. Assign trained standby person who remains outside confined space, maintains contact with entrant, and can activate emergency rescue 9. Provide retrieval equipment including full-body harness, tripod, and rescue winch for vertical entries enabling non-entry rescue capability 10. Brief all personnel on emergency procedures including evacuation signals, rescue activation, and prohibition on untrained entry for rescue attempts 11. Maintain communication between entrant and standby person through voice contact, radio, or line-of-sight as appropriate 12. Document all confined space entries including atmospheric readings, duration, personnel, and any incidents for continuous improvement

Download complete control procedures

Personal protective equipment

Safety Boots with Steel Toe Caps

Requirement: Steel-capped safety boots meeting AS/NZS 2210.3, with penetration-resistant midsole, slip-resistant outsole suitable for muddy conditions, and ankle support for uneven ground.

When: Required at all times on drainage work sites. Ankle support essential when working in trenches with unstable footing. Waterproof construction recommended for wet excavations.

High-Visibility Clothing

Requirement: Class D day/night high-visibility garments meeting AS/NZS 4602.1, with reflective striping providing 360-degree visibility and fluorescent background material.

When: Required when working in roadways, traffic areas, or any location where excavators, trucks, or other mobile plant operate. Must be worn over any other protective clothing.

Waterproof Gloves for Sewage Work

Requirement: Nitrile or neoprene waterproof gloves minimum 0.38mm thickness meeting AS/NZS 2161.1, with extended cuffs covering forearms and textured grip for wet conditions.

When: Required for all work involving contact with sewage, wastewater, or contaminated materials including connection to existing drains, clearing blockages, or working in manholes.

Eye and Face Protection

Requirement: Safety glasses meeting AS/NZS 1337.1 with side shields for general work. Face shield meeting AS/NZS 1337.1 required for cutting into existing drains or high-pressure cleaning operations.

When: Safety glasses required for all drainage installation work. Face shield required when splash or aerosol exposure from sewage is possible during drain cutting or cleaning.

Respiratory Protection

Requirement: P2 particulate respirator meeting AS/NZS 1716 for dust and aerosol protection. Half-face respirator with combination P2+organic vapour cartridges for sewage work with aerosol exposure.

When: Required when dust levels exceed comfort levels during excavation or backfilling. Combination respirator required for cutting into drains or high-pressure cleaning where sewage aerosols are generated.

Confined Space Full-Body Harness

Requirement: Full-body harness meeting AS/NZS 1891.1 with dorsal and front D-rings, adjustable sizing, and compatible with tripod rescue system. Tripod and rescue winch meeting AS/NZS 1891.3.

When: Required for confined space entry including manholes, inspection pits, and pump stations. Harness must be worn by entrant and connected to retrieval system enabling non-entry rescue.

Hard Hat

Requirement: Type 1 safety helmet meeting AS/NZS 1801, protecting against impact from falling objects and overhead hazards.

When: Required when working in excavations with overhead hazards, when excavators or other plant operate nearby potentially dropping materials, or when specified by principal contractor.

Inspections & checks

Before work starts

✓Verify all workers hold current plumbing licences appropriate for drainage work being performed
✓Confirm Dial Before You Dig service enquiry submitted and plans received for electrical, gas, water, telecommunications, and other services
✓Conduct physical service location using electromagnetic locators and ground penetrating radar, marking all located services
✓Inspect trench support equipment including trench boxes, hydraulic shores, or sheet piling for damage, certification current, and operational condition
✓Check atmospheric testing equipment for confined space entry is calibrated within certification period and operational
✓Verify excavation equipment including excavators, trucks, and hand tools are in safe working condition with pre-start checks completed
✓Confirm all workers have appropriate PPE including safety boots, high-visibility clothing, gloves, eye protection, and confined space equipment if required
✓Review excavation plan including proposed depths, support requirements, access arrangements, and emergency procedures with all workers
✓Establish hand washing facilities at work site with soap, running water, and paper towels for sewage-contaminated work
✓Verify first aid kit available with appropriate supplies for treating contaminated wounds, and trained first aider identified
✓Confirm emergency contact numbers displayed and emergency procedures reviewed with all workers including confined space rescue
✓Check weather forecast for work period, verifying no heavy rain predicted that could flood excavations or trigger collapse

During work

✓Monitor excavations continuously for signs of ground movement, water infiltration, or deteriorating stability requiring additional support
✓Verify trench support systems remain correctly positioned and fully effective throughout work period
✓Maintain exclusion zones around excavations preventing vehicles, plant, and stockpiled materials from approaching trench edges
✓Ensure safe access and egress remains available for all excavations deeper than 2 metres with ladders or ramps positioned appropriately
✓Conduct atmospheric testing before any confined space entry and continuous monitoring during entry, with standby person maintaining contact
✓Monitor workers for signs of fatigue, injury, or illness particularly sewage exposure symptoms requiring immediate medical assessment
✓Verify correct pipe grades and falls being achieved during installation using spirit levels, laser levels, or gradient measurement tools
✓Ensure all joints and connections properly made per specifications for pipe material and type being installed
✓Maintain site housekeeping with materials organised, trip hazards eliminated, and waste properly managed
✓Check that bypass pumping (if installed) continues to operate effectively diverting flows from work area

After work

✓Conduct final inspection of installed drainage verifying correct grades, joint quality, and alignment before testing
✓Perform drainage testing per specifications using water testing, air testing, or smoke testing to verify system integrity
✓Document test results including pressures achieved, duration of test, and pass/fail determination with signatures
✓Inspect backfilling ensuring proper bedding materials used, compaction achieved per specifications, and no voids remain around pipes
✓Verify trench support equipment safely removed with no workers exposed to unsupported excavation walls during removal
✓Restore surface finishes to pre-existing condition or as specified including reinstatement of pavements, landscaping, or other features
✓Remove all waste materials including contaminated PPE, packaging, and off-cuts, disposing per environmental regulations
✓Decontaminate all equipment exposed to sewage before removal from site or storage
✓Document any service strikes, near-misses, or incidents during the work including investigation findings and corrective actions
✓Complete handover documentation including as-installed drawings, test certificates, material certifications, and variations from plans

Step-by-step work procedure

Give supervisors and crews a clear, auditable sequence for the task.

Field ready

Service Location and Site Preparation

Begin drainage installation with comprehensive service location and site preparation to identify underground services and establish safe working conditions. Submit Dial Before You Dig enquiry minimum two business days before excavation, providing accurate site location and proposed excavation extent. Review all service plans received identifying electrical, gas, water, telecommunications, and other services within or near the excavation area. Conduct physical service location using electromagnetic cable locators for metallic services and ground penetrating radar for non-metallic plastic pipes, systematically sweeping the entire excavation footprint. Mark all located services on ground surface using colour-coded spray paint following Australian standards (red-electrical, yellow-gas, blue-water, orange-telecommunications). Where services are indicated by plans but not physically located, implement hand digging or vacuum excavation to expose and verify location before proceeding. Establish site controls including barriers around work area, signage warning of excavations, traffic management if in roadway, and access restrictions preventing unauthorised entry. Position stockpile areas for excavated spoil ensuring minimum 1 metre setback from excavation edges. Set out drainage alignment using string lines, laser levels, or other appropriate methods verifying correct horizontal alignment and grades.

Safety considerations

Service strikes can cause electrocution, gas explosions, or flooding requiring comprehensive location and verification before excavation. Traffic hazards when working in roadways require high-visibility clothing and traffic control. Manual handling of service location equipment and setup materials can cause musculoskeletal strain.

Excavation and Trench Support Installation

Excavate drainage trench to required depth and width using appropriate equipment and installing trench support systems as depth increases. Begin excavation using mechanical excavator for bulk removal, maintaining minimum 500mm clearance from located underground services and reducing to hand digging within 300mm of services. Excavate progressively, installing trench support as depth exceeds 1.5 metres—never permit workers to enter unsupported excavations deeper than 1.5 metres regardless of soil appearance. Install trench boxes or shields positioning to provide complete protection for work area, or implement hydraulic shoring with walers and struts at specified spacing (typically 1.2-1.5 metres vertically), or install sheet piling with appropriate bracing for extended trenches. Stockpile excavated spoil minimum 1 metre from trench edges preventing surcharge loading that could trigger collapse. Provide safe access and egress for excavations deeper than 2 metres using securely positioned ladders, ramps, or stairways, located so workers are never more than 5 metres from exit point. Install edge protection barriers preventing falls into excavations. Inspect excavation base removing loose material, achieving specified width, and preparing for bedding material placement.

Safety considerations

Trench collapse can bury and asphyxiate workers requiring comprehensive support systems for excavations deeper than 1.5 metres. Excavator operation near workers creates struck-by and crushing hazards requiring exclusion zones. Manual handling during support installation can cause musculoskeletal injuries. Falls into excavations can cause serious injuries or fatalities requiring edge protection.

Pipe Bedding and Initial Pipe Laying

Prepare pipe bedding and commence drainage pipe installation to specified grades and alignments. Place bedding material in trench base—typically 100-150mm depth of clean sand, graded aggregate, or cement-stabilised sand per specification—compacting appropriately and screeding to achieve uniform thickness and correct gradient for drainage fall. Verify bedding grades using spirit level, laser level, or gradient measurement tools ensuring specified fall is achieved (typically 1:40 to 1:100 depending on pipe diameter and application). Lower first pipe length into trench using mechanical excavator lifting attachment, team lifting, or other appropriate handling method preventing damage to pipe or worker injury. Position pipe accurately on prepared bedding verifying correct alignment horizontally and vertically. For PVC solvent-welded drainage, prepare pipe ends by chamfering and cleaning, apply solvent cement per manufacturer instructions, and join pipes ensuring full insertion to shoulder mark. For rubber ring jointed pipes, clean pipe ends and socket, lubricate rubber ring, and push-fit ensuring ring remains correctly positioned. Continue pipe laying progressively, maintaining specified grades and checking alignment regularly. Support pipes during installation preventing movement before bedding is completed around pipes.

Safety considerations

Manual handling of pipes into trenches risks musculoskeletal injuries requiring mechanical aids or team lifting. Solvent cement for PVC pipes contains volatile solvents requiring ventilation and avoidance of ignition sources. Working in excavations presents ongoing collapse risks requiring maintained trench support. Contact with bedding materials can cause skin irritation requiring gloves.

Connection to Existing Drainage Systems

Connect new drainage to existing sewer or stormwater systems following procedures that minimise sewage exposure and maintain system integrity. If connection requires entry to manholes or inspection pits, implement confined space entry procedures including atmospheric testing for oxygen, hydrogen sulfide, methane, and carbon monoxide, forced-air ventilation, standby person assignment, and emergency rescue provisions. Implement bypass pumping if practical to divert active flows around connection point reducing sewage exposure. Excavate carefully around existing drain to be connected, hand digging to expose connection point without damaging existing infrastructure. For connections involving cutting into existing pipes, don complete PPE including waterproof gloves, face shield, and respiratory protection against sewage aerosols. Cut into existing drain using appropriate methods for pipe material—saw cutting for PVC or concrete, carefully breaking for earthenware taking care not to propagate cracks beyond intended cut. Control sewage spillage using absorbent materials, pumps, or temporary plugs as appropriate. Install junction fitting, tee, or penetration as required for connection type, ensuring proper sealing and structural support. Verify connection is secure, sealed, and properly aligned before proceeding. Clean work area removing sewage-contaminated materials and decontaminating tools and equipment.

Safety considerations

Sewage exposure during connection can transmit serious diseases including leptospirosis requiring PPE, hygiene protocols, and medical surveillance. Confined space entry for manhole work presents atmospheric hazards requiring testing, ventilation, and standby personnel. Cutting into existing drains generates aerosols requiring respiratory protection. Unexpected sewage flows during connection can flood work areas.

Installation of Junctions, Inspection Points, and Fittings

Install junction boxes, inspection openings, access points, and fittings at specified locations within the drainage system. Position junction boxes on prepared bedding ensuring base is level and stable. Connect incoming drainage pipes to junction box inlets ensuring correct alignment, proper jointing per pipe material and junction box type, and verification that inlets are at correct heights relative to outlet maintaining drainage fall through the junction. Install junction box lid or cover with appropriate traffic loading rating—Class A for pedestrian areas, Class B for light vehicles, or Class C for heavy traffic. For inspection openings (IOs) and access points, install per specifications ensuring covers are flush with finished surface level, appropriately traffic-rated, and securely positioned. Install bends, reducers, and other fittings as required maintaining correct alignment and ensuring all joints are properly made. Where drainage system includes gully traps, install ensuring correct height relative to finished surface, proper connection to drainage pipes, and grate or cover fitted appropriately. Verify all junctions and fittings are securely positioned, properly bedded, and supported before proceeding with surrounding backfill.

Safety considerations

Manual handling of junction boxes and heavy fittings can cause musculoskeletal injuries requiring mechanical assistance or team lifting. Working in trenches with fittings requires careful footing on unstable ground. Confined trench environment limits working space increasing injury risk during lifting and positioning tasks.

Drainage Testing and Verification

Test completed drainage installation to verify system integrity and compliance with specifications before backfilling conceals the work. Conduct testing method specified for the drainage type—typically water testing for sanitary drainage, air testing for verification of joint integrity, or smoke testing to identify leaks. For water testing, install test plugs at system extremities, fill system with water to specified test head (typically 1.5 metres above invert level or to top of highest fitting), and monitor for specified test period (typically 30 minutes for PVC systems, longer for other materials) verifying water level remains constant within specified tolerances. Document initial water level, final water level, test duration, ambient temperature, and pass/fail determination. For air testing, install test plugs, pressurise system to specified test pressure (typically 50-100mm water gauge), isolate pressure source, and monitor pressure for test duration (typically 5 minutes) verifying pressure loss remains within specification. For smoke testing, introduce non-toxic smoke into plugged system and observe for smoke emergence indicating leaks. Investigate and remediate any test failures before proceeding—leaking joints may require excavation to access failed joint, cleaning, and re-jointing. Re-test following any remediation to verify correction. Document all test results with photographs, data sheets, and certification.

Safety considerations

Pressurised testing introduces risks of sudden pressure release if system fails requiring workers to maintain clear of test area during pressurisation. Confined space entry may be required for installing test plugs in manholes requiring atmospheric testing and standby personnel. Manual handling of test equipment and water filling apparatus can cause musculoskeletal strain. Smoke testing chemicals require appropriate ventilation and respiratory protection per Safety Data Sheets.

Backfilling, Compaction, and Surface Restoration

Following successful testing, backfill and compact trenches restoring surface to pre-existing condition or as specified. Place initial backfill layer around pipes—typically 150-300mm of bedding-type material (clean sand or graded aggregate)—carefully ensuring pipes are not displaced and joints are not stressed during placement. Compact initial backfill layer gently around pipe haunches using hand-operated compaction equipment avoiding damage to pipes. Continue backfilling in layers not exceeding 300mm compacted thickness, using appropriate backfill materials per specification and compacting each layer systematically to achieve specified density (typically 95-98% maximum dry density per standard compaction test). For deeper excavations, progressively remove trench support as backfilling proceeds, ensuring no workers are exposed to unsupported excavation walls during support removal. Restore surface finishes matching pre-existing conditions including placement and compaction of road base materials, reinstatement of pavement surfaces using appropriate methods (asphalt, concrete, or pavers matching existing), restoration of landscaping including topsoil placement and turf or planting reinstatement, and cleaning of work area removing excess materials, waste, and equipment. Dispose of surplus excavated material and waste per environmental regulations. Complete as-constructed documentation including actual trench depths, pipe locations, deviations from plans, and any services encountered or relocated.

Safety considerations

Compaction equipment operation creates noise requiring hearing protection and vibration exposure requiring work rotation. Backfilling operations present burial risks requiring workers to remain clear of trench during material placement. Removing trench support exposes workers to collapse risks requiring careful sequencing with backfilling. Manual handling during backfilling and surface restoration can cause musculoskeletal injuries particularly during prolonged shovelling and raking tasks.

Get risk assessment & procedures

Frequently asked questions

What are the legal requirements for trench support in drainage excavations?

Australian WHS regulations require trench support for excavations deeper than 1.5 metres, with specific requirements based on soil type, excavation depth, proximity to structures, and duration of excavation. The regulations prohibit any person from entering an excavation deeper than 1.5 metres unless the excavation is supported by shoring, shielding, or other appropriate means to prevent collapse, or the sides of the excavation are battered or benched back to a safe angle. For soil types, sandy or gravelly soils require support at shallower depths than clay soils due to lower stability. Excavations near structures, services, or subject to vibration from traffic or equipment require enhanced support regardless of depth. The legal standard is based on AS 2870 Residential Slabs and Footings and general excavation safety principles requiring competent person assessment of soil conditions and support requirements. Penalties for non-compliance are severe, particularly following incidents, with WorkSafe able to issue prohibition notices immediately stopping work, improvement notices requiring remediation, and prosecutions following serious incidents or fatalities that can result in fines exceeding $500,000 for companies and $100,000 for individuals. From a practical perspective, the legal minimum should be viewed as exactly that—a minimum requirement. Best practice involves implementing trench support whenever depth, soil conditions, or site factors create any doubt about stability, erring on the side of caution to protect workers from the catastrophic consequences of collapse.

How do I ensure compliance with AS/NZS 3500 standards for drainage installation?

Compliance with AS/NZS 3500.2 Sanitary Plumbing and Drainage and AS/NZS 3500.3 Stormwater Drainage requires systematic attention to design, materials, installation, and testing requirements specified throughout these comprehensive standards. Begin with design compliance ensuring drainage systems are properly sized based on fixture unit calculations for sanitary drainage or catchment area and rainfall intensity for stormwater, with minimum pipe diameters, grades, and layouts meeting standard requirements. Material selection must comply with approved materials listed in the standards, with pipes, fittings, and jointing methods appropriate for the specific application and correctly specified for expected loads and conditions. Installation practices must follow standard requirements including minimum cover depths protecting pipes from damage (typically 600mm under trafficked areas, 300mm under non-trafficked areas, with variations for specific pipe materials), proper pipe bedding and backfilling using specified materials and compaction, correct jointing procedures for each pipe material ensuring leak-free connections, and provision of inspection openings and access points at required intervals and locations. Testing is mandatory with the standards specifying test methods (water testing, air testing), test durations, allowable leakage rates, and documentation requirements. Inspection opening spacing is specified based on pipe diameter and system complexity, typically every 45-75 metres for residential installations and more frequently for commercial systems. Maintain compliance documentation including design calculations, material certifications, test results, and as-constructed drawings demonstrating conformance with all applicable standard requirements. Non-compliance can result in work rejection by building surveyors or water authorities, requirements for correction at contractor expense, and potential liability for failures or defects arising from non-compliant installations.

What procedures should I follow when I need to connect to existing live sewer systems?

Connecting to existing live sewer systems requires careful planning and implementation of specific controls to protect workers from sewage exposure and ensure system integrity is maintained. Pre-work planning should include coordination with building occupants, facility managers, or municipal authorities to minimise discharge during connection work, scheduling connections during lowest-flow periods (typically overnight or early morning for municipal sewers, during business closures for commercial buildings), and implementing temporary bypass pumping where practical to divert flows around the connection point. Before any work commencing, implement confined space entry procedures if manhole or inspection pit access is required, including atmospheric testing for oxygen, hydrogen sulfide, methane, and carbon monoxide, forced-air ventilation throughout the work period, standby person assignment maintaining contact with entrants, and emergency rescue provisions. Workers must don complete sewage-work PPE before any contact with existing systems including waterproof gloves, face shields, protective clothing, and respiratory protection when aerosol exposure is anticipated during cutting operations. Excavate carefully around the existing drain to expose the connection point, using hand tools to prevent damage to the existing infrastructure. When cutting into the existing drain, control sewage spillage using absorbent materials, temporary plugs, or small pumps as appropriate, with waste materials treated as contaminated requiring proper disposal. Make the connection quickly and efficiently to minimise duration of system breach, using appropriate junction fittings or penetration methods for the pipe materials involved, and verifying proper sealing before removing temporary controls. Following connection completion, test the new installation and verify no leakage at the connection point before backfilling. Thoroughly clean and decontaminate all tools, equipment, and PPE exposed to sewage. All workers involved in sewage connection work should be vaccinated against hepatitis A and B and maintain current tetanus vaccination, with protocols for immediate medical assessment following significant exposures or development of symptoms suggesting sewage-related illness.

What testing methods are acceptable for different types of drainage systems?

Australian Standards specify testing methods appropriate for different drainage system types ensuring leak-free, compliant installations. For sanitary drainage (sewerage), water testing is the primary specified method involving installation of test plugs at system extremities, filling with water to specified test head (typically 1.5 metres above invert level or to top of highest fixture), and monitoring for specified period (typically 30 minutes for PVC systems) with water loss limits not exceeding 0.05 litres per metre of pipe diameter per metre of pipe length. Air testing provides an alternative involving pressurising the plugged system to 50-100mm water gauge and monitoring pressure loss over typically 5 minutes, with acceptance criteria specifying maximum allowable pressure drop. For stormwater drainage, water testing is similarly specified with test heads and durations appropriate to pipe size and material. Smoke testing is sometimes used for identifying leaks in completed systems, introducing non-toxic smoke into the plugged system and observing for smoke emergence at joints, connections, or pipe damage. For pressure sewer systems (rising mains), hydrostatic pressure testing to higher test pressures (typically 1.5 times operating pressure) for extended durations (typically 2 hours) is required to verify system integrity under design operating conditions. Test pressures, durations, and acceptance criteria vary based on pipe material—PVC, concrete, earthenware, and polyethylene each have specific requirements in AS/NZS 3500.2. All testing must be documented including test method, test pressure or head, duration, ambient temperature (affecting test results particularly for PVC systems), water loss or pressure drop measured, pass/fail determination, and tester identification. Failed tests require investigation to identify leaking joints or damaged pipes, remediation by re-jointing or replacement as necessary, and re-testing to verify correction. Never backfill drainage installations before successful completion and documentation of required testing, as excavating to identify leaks after backfilling is extremely costly and disruptive.

How should I manage the risk of existing services when excavating for drainage?

Managing underground service risks during drainage excavation requires a comprehensive, systematic approach combining service information gathering, physical location, careful excavation practices, and emergency response planning. The process begins with mandatory Dial Before You Dig enquiry submitted at least two business days before excavation, providing accurate location details of the proposed work area. The response provides service plans from utilities and asset owners indicating approximate locations of electrical, gas, water, telecommunications, and other underground infrastructure. Critically, these plans show approximate locations based on historical records and should never be relied upon as exact—actual service locations can vary from plans by significant distances particularly in older urban areas. Supplement plans with physical service location using electromagnetic cable locators (detecting electrical cables, metallic water and gas pipes, and telecommunications cables with metallic tracer wires) and ground penetrating radar (detecting non-metallic services including plastic gas and water pipes that electromagnetic locators cannot find). Mark all located services on the ground surface using colour-coded spray paint or pegs following Australian standard colour codes. Where services are indicated by plans but cannot be physically located, implement hand digging or vacuum excavation to physically expose and verify the service location before proceeding with mechanical excavation. When excavating near located services, maintain minimum clearances of 300mm for hand digging and 500mm for mechanical excavation, reducing to hand digging when approaching the 300mm clearance. Brief excavator operators specifically on service locations, required clearances, and procedures to follow if services are exposed or struck. Implement a spotter system with a worker observing excavation and monitoring clearances when mechanical excavation approaches located services. If services are exposed during excavation, support them appropriately to prevent damage from undermining, and protect from construction traffic and activities. Should a service strike occur, implement emergency procedures including immediate work cessation, evacuation of workers from the immediate area, notification to the affected utility and emergency services, establishment of exclusion zone, and prohibition on re-starting work until the service owner has inspected, made safe, and authorised work resumption. Never assume service locations based solely on plans—always verify physically before excavating, and maintain extreme caution even with comprehensive location efforts as services can be mis-located, unmarked services may exist, and conditions can change during excavation requiring constant vigilance.

Overview

Plumbing drainage work encompasses the installation, repair, and modification of below-ground and above-ground drainage systems that convey wastewater, sewage, and stormwater from buildings and properties to treatment facilities or disposal points. Drainage installations must be completed to exacting standards as failures can result in environmental contamination, public health risks, structural damage from water infiltration, and costly remediation. The work involves extensive excavation and trenching to install underground pipes, careful placement and grading to achieve required falls for gravity systems, connection to existing infrastructure, comprehensive testing to verify system integrity, and proper backfilling and compaction to prevent ground settlement and pipe damage.

Why This SWMS Matters

Drainage installation is classified as high-risk construction work under Australian WHS regulations due to the inherent dangers of excavation, trenching, working near underground services, and potential for trench collapse. Workers have suffered fatalities and serious injuries from trench cave-ins, striking underground electrical cables and gas mains, contact with sewage and contaminated material, and falls into excavations. The Work Health and Safety Act 2011 requires comprehensive risk management for these activities including preparation of Safe Work Method Statements before commencing work. This SWMS implements appropriate controls following the hierarchy of control, establishes clear procedures for safe drainage installation, and ensures compliance with WHS legislation, Australian Standards for plumbing and drainage, and industry best practices that protect workers, the public, and the environment.

Trusted by 1,500+ Australian construction teams