SWMS template · Excavation & Earthworks
Septic Tank and Pump Well Installation — Safe Work Method Statement
Safe Work Method Statement for installing septic tanks, aerated wastewater treatment system tanks and pump wells, covering excavation of the tank pit, decommissioning the old system, lifting the tank in, anchoring against flotation, backfilling and connecting pumps and alarms.
- Category
- Excavation & Earthworks
- HRCW
- 3 categories
- Job steps
- 7
- Hazards rated
- 20
- PPE items
- 8
This SWMS covers installing a new precast concrete or polyethylene septic tank, aerated wastewater treatment system (AWTS) tank or sewage pump well, including replacing an old system. The tank pit is usually well over 1.5 metres deep, the tank is placed with a crane truck or excavator, and workers often get into the pit to set the bedding and make the inlet and outlet connections. That makes it High Risk Construction Work for excavation deeper than 1.5 metres and powered mobile plant, and where you are working at or near an existing tank or pump well it is also work near a confined space. A SWMS is required.
The hazards specific to this job are collapse of the pit while someone is in it levelling the base or connecting pipes; a heavy tank (a precast concrete tank can weigh several tonnes) falling or swinging during the lift; the tank floating out of the ground or cracking when groundwater is high and the tank is empty; and sewage, hydrogen sulfide and methane in existing tanks and pump wells. Nobody enters an existing tank or pump well under this SWMS. If entry is unavoidable it needs a confined space entry permit and its own SWMS. Old tanks must be pumped out by a liquid waste contractor before they are removed, filled or broken up, and open tanks left unattended are a real drowning risk, especially for children.
On-site wastewater systems generally need approval from the local council, and drainage work and connections must be done by a licensed plumber or drainer. Pumps, floats and alarms must be wired by a licensed electrician. The crane truck operator needs the high risk work licence for that crane type, and slinging out of the operator's view needs a licensed dogger. If you use an excavator to lift the tank, the machine must be rated for lifting (see the Excavator Lifting Operations template). Requirements vary between councils and states, so check with your council and your state or territory regulator.
The SWMS must address ground support for the pit, spoil and plant set-back from the edge, dewatering, how and when workers enter the pit, the lift plan for the tank, anchoring or ballasting against flotation, backfill method, and the decommissioning of any old system.
Customise this template with the tank type, size and weight, the council approval reference, the pit depth and ground support method, groundwater level, the crane or excavator used and the lift plan, the manufacturer's backfill and anchoring requirements, the liquid waste contractor for any old system, the licensed plumber and electrician, and the BYDA reference.
Important: This SWMS template is a starting point only. Review and customise it for your workplace and task. The PCBU remains responsible for ensuring the SWMS is suitable for the work. Not legal advice.
High Risk Construction Work Types
- Work in or near a shaft or trench deeper than 1.5 metres, or a tunnel
- Work in an area with movement of powered mobile plant
- Work in or near a confined space
Personal Protective Equipment
- Hard hat
- High-visibility clothing
- Steel-capped safety boots or steel-capped gumboots
- Safety glasses
- Waterproof nitrile gloves (long cuff) when handling sewage-contaminated material
- Rigger's gloves for slinging
- Hearing protection when using compactors
- Face shield when working near pumped sewage or effluent
Risk Assessment
RatingsCatastrophicHighModerateLow
Step 1Site assessment, approvals and services location
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Striking buried power, water, gas or communications services | Catastrophic | Get BYDA plans and locate private services (house power to sheds and pumps, water lines, existing drains) with a locator. Expose services by hand or vacuum excavation within the asset owner's zone before machine digging. | Moderate | Supervisor |
| Crane truck or plant collapsing an existing tank, drain or soakage area | High | Locate the existing tank, pipes and disposal field before plant arrives. Mark them and keep heavy vehicles and outriggers off them. Set the crane up on firm ground using outrigger pads. | Low | Supervisor / Crane Operator |
| Overhead powerlines near the crane truck or excavator | Catastrophic | Identify overhead lines, including the property's service line. Plan the crane position and lift path to stay outside the approach distance set by your state's electrical safety rules, with a safety observer where needed. | Moderate | Supervisor / Crane Operator |
Step 2Decommissioning the existing system (if replacing)
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Exposure to hydrogen sulfide and methane from the open tank | High | Have the old tank pumped out by a licensed liquid waste contractor before work. Open lids from the upwind side and stand back. No entry into the tank. No smoking or ignition sources near open tanks. | Low | Supervisor / Liquid Waste Contractor |
| Infection from sewage contact | Moderate | Wear long-cuff waterproof gloves and eye protection. Wash hands before eating, drinking or smoking. Cover cuts. Hepatitis A and tetanus vaccinations recommended for workers who regularly handle sewage. Clean and disinfect tools at the end of the job. | Low | All Workers |
| Person or child falls into an open tank | Catastrophic | Never leave an open tank unattended. Cover with a secured lid or plate strong enough to walk on, and fence the area. Remove, break up or fill the old tank as the council requires. | Low | Supervisor |
Step 3Excavating the tank pit
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Pit wall collapse onto a worker | Catastrophic | Batter, bench or shore the pit to the excavation plan before anyone enters. Assess soil type and groundwater before digging. Inspect the pit before each entry and after rain. | Moderate | Supervisor / Excavator Operator |
| Spoil or plant surcharging the pit edge | High | Keep spoil at least 1 metre back from the edge, further in poor ground. Keep the crane truck and excavator back from the edge by the distance set in the excavation plan. | Low | Excavator Operator |
| Groundwater or rain flooding the pit and destabilising the walls | High | Use a submersible pump to keep the pit dry. Discharge water away from the pit edge. Stop and reassess the walls if seepage increases. | Moderate | Supervisor |
| Person or vehicle falls into the open pit | High | Fence the pit with temporary fencing whenever it is unattended, including overnight. Barricade plant approaches. | Low | Supervisor |
Step 4Preparing the base in the pit
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Worker in the pit struck by the excavator bucket | High | Excavator stops, lowers the bucket and engages the hydraulic lockout before anyone enters the pit. Material is placed only when workers are clear. | Low | Excavator Operator / Supervisor |
| Carbon monoxide from a petrol plate compactor in a deep pit | High | Use an electric or diesel compactor where possible, or compact bedding from outside the pit. If a petrol compactor must be used, limit run time and monitor carbon monoxide. Stop if anyone feels dizzy or gets a headache. | Low | Supervisor |
| Fall or no way out of the pit | Moderate | Secured ladder extending 1 metre above the pit edge, placed within the supported area. | Low | Supervisor |
Step 5Lifting and placing the tank
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Tank falls or rigging fails during the lift | Catastrophic | Confirm the tank weight from the manufacturer. Prepare a lift plan with weight, radius and crane chart capacity. Lift only from the manufacturer's lifting points with rated, tagged slings and shackles. Crane operator holds the right licence class; a licensed dogger slings and directs the lift. Nobody in the pit or under the load. | Low | Crane Operator / Dogger / Supervisor |
| Tank swings and crushes a worker against the pit wall or plant | High | Use tag lines to control the tank. Lower slowly into the pit. Workers enter the pit only after the tank is landed, level and stable and the slings are slack. | Low | Dogger / Crane Operator |
Step 6Anchoring, connecting pipework and backfilling
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Tank floats or cracks due to groundwater or uneven backfill | High | Follow the manufacturer's backfill and anchoring instructions. Fill the tank with water progressively as backfill goes in where the manufacturer requires it. Install anchors or ballast where groundwater is high. Backfill evenly around the tank in layers. | Low | Plumber / Supervisor |
| Manual handling of lids, risers and pipe | Moderate | Use two people or a lifting aid for heavy lids and risers. Use the excavator to place heavy pipe and materials near the pit, not hand-carry them down ladders. | Low | All Workers |
| Connection to a live sewer or existing drain releases sewage or gas | Moderate | Licensed plumber or drainer to make all connections. Stop upstream use of the plumbing during the connection. Wear long-cuff gloves and eye protection. | Low | Licensed Plumber |
Step 7Electrical connection, commissioning and handover
| Hazard / Risk | Initial Risk | Control Measures | Residual Risk | Responsibility |
|---|---|---|---|---|
| Electric shock from pump, float or alarm wiring | High | All wiring of pumps, floats, aerators and alarms done and tested by a licensed electrician. Isolate and lock out at the switchboard before working on any connected pump. Pump circuits protected by an RCD. | Low | Licensed Electrician |
| Person falls into the tank or pump well after handover | High | Fit the manufacturer's lids and secure them with bolts or locks so they cannot be opened without tools. Check lids and risers are rated for any expected loads. Brief the owner on not opening the tank. | Low | Plumber / 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.
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