Drainage Installation — Safe Work Method Statement
Safe Work Method Statement for the installation of sanitary drainage, stormwater drainage, and sewer connection systems for residential and commercial buildings in compliance with AS/NZS 3500.2 and relevant state plumbing regulations.
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Drainage installation encompasses sanitary drainage (from sanitary fixtures to the sewer connection point), sewer connections (the junction with the public sewer), and stormwater drainage (from roof and surface runoff to the legal point of discharge). All this work must be performed by a licensed plumber and drainer holding the relevant licence class in their state or territory. The work must comply with AS/NZS 3500.2 (Sanitary plumbing and drainage) and AS/NZS 3500.3 (Stormwater drainage), and must be inspected and certified under the state plumbing inspection regime before being covered or backfilled.
Drainage installation almost always involves excavation — and frequently involves trenches exceeding 1.5 m depth for deep sewer connection points, making the excavation component HRCW under Schedule 3 of the model WHS Regulations. A SWMS must address both the plumbing work and the excavation in a single integrated document or through cross-referenced SWMS documents. Dial Before You Dig (1100) must be contacted and service plans obtained before any excavation commences, and potholing must be used to confirm actual service positions within 500 mm of indicated locations.
New sewer connections in most Australian states require formal approval from the relevant water authority before work commences. In NSW, a Section 68 approval under the Local Government Act is required. In Queensland, an Application for Sewerage Works must be submitted to the relevant council or water authority. Sewer connections must not be made live — the authority will typically isolate the sewer or direct the time of connection to avoid sewage surcharge during the connection process.
Gravity drainage systems must be installed at the correct falls per AS/NZS 3500.2 — typically a minimum 1:40 for DN 100 mm pipes. Incorrect falls cause blockages and sewer surcharge that are costly to rectify after backfill. CCTV inspection of newly installed drainage prior to backfill is increasingly specified by principal contractors and councils.
Customise this template with the drainage system type, the trench design, the authority connection approval reference, and the inspection and testing requirements. This SWMS applies in all Australian states and territories.
Personal Protective Equipment
High Risk Construction Work Types
- •Excavation to a depth of more than 1.5 metres
- •Work near energised underground services
Risk Assessment
1.Site Survey and Underground Service Location
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Undetected sewer or stormwater crossing causing pipe damage and contamination | High | Obtain a DBYD response and water authority drainage plans before commencing any work. Compare plans against the physical site layout; note any discrepancies. Use electromagnetic locating equipment to scan for metallic services and probe with a thin steel rod to locate non-metallic pipes near the proposed excavation line. Mark all detected services on the ground surface before excavation. Hand-dig within 300 mm of all marked service locations to physically identify the service depth and position. | Low | Licensed Plumber / Site Supervisor |
2.Excavation for Drain Trenches
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Cave-in of trench walls injuring or burying a worker | Catastrophic | Assess soil conditions before excavation. For trenches in Class C or D soil (poorly graded or saturated) or any trench deeper than 1.5 m, engage a geotechnical engineer to determine required batter or shoring. Install trench shields or hydraulic shoring per the engineer's specification before workers enter. Conduct a hazard inspection of trench walls before each entry. Never allow workers to work in the trench during rainfall events that could saturate walls. Place spoil at least 1 m from the trench edge. | Moderate | Excavation Supervisor / Licensed Plumber |
| Struck by excavator bucket or moving plant | High | Establish a 5-metre exclusion zone around the excavator swing radius using high-visibility bunting. No workers may enter the exclusion zone while the excavator is operating. The excavator operator must spot the work area clear of personnel before swinging the boom. When workers need to work near the excavator (e.g. to inspect depth or position pipes), the operator must place the bucket on the ground, disengage the swing drive, and receive a clear verbal signal from the supervisor before workers approach. | Low | Excavator Operator / Site Supervisor |
3.Pipe Bedding and Laying
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Back injury from manual handling of heavy concrete or clay pipes in trench | High | Concrete and clay pipes above 20 kg (typically DN100 and larger) must be lowered into the trench using a crane or excavator with a rated pipe hook attachment — never thrown or dropped. Workers in the trench to guide the pipe into position using ropes or guide bars, keeping hands away from the pipe spigot and socket during insertion. Minimise manual re-positioning in the trench using the mechanical plant where possible. Workers must not lift and carry pipes in a trench — roll or slide pipes on the bedding material. | Low | Licensed Plumber / Site Supervisor |
4.Cutting and Jointing Pipes
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Silica dust inhalation from cutting concrete or clay pipes | High | Use a wet-cut saw with continuous water suppression when cutting concrete or clay pipes. Workers and bystanders within 4 metres of the cutting zone must wear a P2 disposable respirator during cutting. Never use an angle grinder on clay or concrete pipe without a dust shroud and vacuum capture. Conduct cutting operations in a well-ventilated area or outdoors. Dampen cut faces before handling. Review silica dust risk assessment per Safe Work Australia guidance on crystalline silica. | Low | Licensed Plumber / All Workers |
| Solvent cement fume inhalation during PVC jointing | Moderate | Use solvent cement in well-ventilated areas — open trenches provide reasonable ventilation but deep or confined sections may require forced air supply. Apply solvent cement with the brush provided by the manufacturer and replace cap immediately after use. Solvent cement containers must not be left open. In confined trenches, limit exposure time and rotate workers to limit individual exposure below the WES. Workers to stand upwind of the application point where possible. | Low | Licensed Plumber |
5.Camera Inspection, Testing, and Backfill
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Flooding of trench during hydraulic testing causing worker entrapment | High | No workers may be inside the trench during hydraulic testing of installed drainage. All workers must be on the surface and clear of the trench during pressurisation or when blocking the drain for a water test. If the test fails and the trench floods, depressurise or remove test plug before allowing workers back in. Pump out trench and re-inspect walls for erosion or softening before re-entry. Ensure a worker observer is stationed at the trench edge throughout the test. | Low | Licensed Plumber / Site Supervisor |
Relevant Codes of Practice
Worker Acknowledgement
By signing below, I confirm that I have read, understood and agree to comply with this Safe Work Method Statement.