Sewer & Drain Confined Space SWMS
Safe work method statement for entry into sewers, maintenance holes, wet wells, pump stations and below-ground drainage structures for inspection, cleaning, repair and connection work.
SWMS variants reference your state’s WHS legislation. Instant download after payment.
Sewer and drain work in confined spaces covers entry into sewers, maintenance holes, wet wells, pump stations, large drains and other below-ground drainage structures to inspect, clean, repair, connect or maintain the drainage system. It is among the most hazardous plumbing work because it combines the confined space itself with the specific hazards of sewers and drains: oxygen-deficient and toxic atmospheres including hydrogen sulphide and methane, biological hazards from sewage, the risk of sudden inflow or surcharge, and restricted entry and egress. A confined space in a sewer can be immediately dangerous to life, and many fatalities have occurred when workers, or those attempting to rescue them, entered without controls. This document is written on the basis that confined space entry for sewer and drain work is carried out under a confined space entry permit with atmospheric testing, ventilation, a standby person and rescue arrangements.
Confined space work is high risk construction work under the model Work Health and Safety Regulations where it is construction work, and is governed by the confined spaces Code of Practice, which requires a risk assessment, an entry permit, atmospheric testing and monitoring, ventilation, and standby and rescue arrangements. Sewer and drainage work is also plumbing work carried out to the relevant parts of AS/NZS 3500, particularly the sanitary plumbing and drainage part. The atmospheric hazards of sewers — oxygen deficiency, hydrogen sulphide, methane and other gases — and the biological hazards of sewage are the defining risks. This document coordinates the confined space entry, atmospheric, biological and inflow controls so the work is carried out without an atmospheric or engulfment incident.
Hazards identified
9 hazards covered, sorted by priority.
Asphyxiation, often without warning, in an oxygen-depleted confined space
Poisoning and rapid incapacitation from toxic atmospheres in sewers
Fire or explosion where flammable sewer gas accumulates
Infection and illness from contact with or ingestion of sewage
Engulfment and drowning from an uncontrolled inflow of sewage or water
Delayed escape and rescue from the confined drainage structure
Multiple fatalities where would-be rescuers enter without controls
Engulfment in sewage, sludge or stored water
Musculoskeletal and impact injury in the confined working position
Control measures
Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.
- 1Engineering: where possible, eliminate entry — inspect and clean by camera, jetting or no-entry methods from the surface so workers do not enter the confined space at all.
- 2Engineering: continuous atmospheric testing and monitoring before and throughout entry for oxygen, hydrogen sulphide, flammable gas and other contaminants, with defined evacuation criteria, and forced ventilation to maintain a safe atmosphere.
- 3Administrative: a confined space entry permit and risk assessment to the confined spaces Code of Practice, with the space isolated from inflow where practicable and the entry controlled.
- 4Administrative: a trained standby person stationed at the entry, continuous communication with the entrant, and documented rescue arrangements that do not rely on unplanned entry by other workers.
- 5Engineering: control inflow and surcharge — isolation, plugging, upstream control or flow diversion — so the structure cannot suddenly fill while workers are inside.
- 6Administrative: manage the biological hazard with hygiene controls, vaccination where appropriate, washing facilities, and prohibition of eating, drinking and smoking until decontaminated.
- 7PPE: appropriate respiratory protection including supplied air for oxygen-deficient or toxic atmospheres, a retrieval harness and line where required, and protective clothing against sewage contact, per AS/NZS 1715 and AS/NZS 1716.
- 8Administrative: ensure the work is carried out and certified by an appropriately licensed plumber or gasfitter under the relevant state or territory plumbing and gasfitting licensing scheme, with a compliance certificate issued where required.
- 9Administrative: all workers must hold a valid White Card (General Construction Induction Training, CPCCWHS1001) before entering any construction workplace, with the plumbing, gasfitting and any confined space competencies and licences required for the work.
- 10Administrative: conduct a daily pre-start toolbox talk covering the day's work, identified hazards, isolations, required PPE and emergency procedures, and record attendance in the consultation section.
- 11Administrative: consult workers and any health and safety representatives on the work and its risks, record the consultation, and keep this document available at the workplace.
- 12PPE: eye protection to AS/NZS 1337.1, hearing protection where required, gloves appropriate to the task, and Class I or Class II safety footwear with protective toecap to AS/NZS 2210.3.
- 13Administrative: review and update this SWMS whenever the work scope changes, after any incident or near miss, when a worker or health and safety representative raises a concern, when new hazards are identified, or at minimum every 12 months.
Applicable Codes of Practice
The risk assessment, entry permit, atmospheric testing, ventilation, standby and rescue requirements for confined space entry into sewers and drainage structures.
The sanitary plumbing and drainage standard for the sewer and drainage work being carried out.
The standard supporting safe working in confined spaces, including atmospheric testing and entry procedures.
Selection and use of supplied-air and other respiratory protection for the oxygen-deficient and toxic atmospheres of sewers.
The risk management process and hierarchy of controls applied to the confined space, atmospheric and biological hazards.
High-Risk Construction Work triggered
Entry into a sewer, maintenance hole, wet well, pump station or large drain is work in a confined space that may be oxygen-deficient or have a contaminated or flammable atmosphere, which is high risk construction work requiring a SWMS before the work commences.
Sewers and drainage structures can surcharge or fill, presenting a risk of drowning or engulfment, bringing the work within this category and driving the inflow-control and rescue arrangements.
Sewer and drain work in a confined space is high risk construction work under the model WHS Regulations, requiring a SWMS prepared before the work commences, kept readily accessible, and given to the principal contractor if one is appointed, and it is governed by the confined spaces Code of Practice. A confined space entry permit, atmospheric testing and monitoring, ventilation, a standby person and documented rescue arrangements are mandatory, and the drainage work is carried out to AS/NZS 3500.2. Confined spaces in sewers are immediately dangerous to life, and fatalities frequently involve would-be rescuers entering without controls, so rescue must never rely on unplanned entry. Breaches of the confined space duties and the primary duty of care under the model WHS Act are actively enforced, with offence categories running from failure-to-comply through to reckless conduct, and the most serious breaches carrying imprisonment for individuals. Body-corporate maxima are substantial and indexed; the current maximum follows the prevailing schedule of the responsible regulator.
Who this is for
- →Licensed plumbers and drainage contractors entering sewers and drainage structures.
- →Sewer and drain maintenance crews working in maintenance holes, wet wells and pump stations.
- →Civil and utility contractors carrying out below-ground drainage connection and repair.
- →Confined space entry teams including standby and rescue personnel.
- →PCBU safety managers and supervisors coordinating the confined space entry permit, atmospheric and rescue controls.
What you receive
- ✓Editable Microsoft Word document (.docx) fully compatible with Microsoft Word 2016 and newer, Google Docs, and LibreOffice Writer.
- ✓Title page with editable fields for PCBU name, ABN, site address, project name, principal contractor details, and document revision date.
- ✓Hazard register with the sewer and drain work in confined spaces hazards — each with a documented consequence, inherent risk rating on a 5x5 likelihood-consequence matrix, hierarchy-of-control measures, and residual risk rating.
- ✓No-entry-first prompts, a confined space entry permit and atmospheric-monitoring section referencing the confined spaces Code of Practice, an inflow-control and rescue-arrangements section, and a biological-hazard and decontamination section.
- ✓Licensing and compliance-certificate prompts for the relevant plumbing and gasfitting scheme, and a respiratory protection selection and fit-test record per AS/NZS 1715 where relevant.
- ✓Worker consultation record per the model WHS Act consultation duty and a worker sign-on register (blank, expandable).
- ✓Applicable legislation and Codes of Practice schedule pre-populated for the model WHS jurisdiction with a state-variance reference table covering the harmonised states, plus Victoria.
- ✓Emergency procedure template and a revision log.
Worked example
A drainage contractor is engaged to repair a collapsed junction in a sewer accessed through a maintenance hole. Because the work requires entry into a confined space in a sewer, it is high risk construction work, a SWMS is prepared, and the work follows the confined spaces Code of Practice. The crew first attempts the repair by camera and no-entry methods from the surface; where entry proves unavoidable, a confined space entry permit and risk assessment are completed. The atmosphere is tested before entry and monitored continuously for oxygen, hydrogen sulphide and flammable gas with defined evacuation criteria, and forced ventilation maintains a safe atmosphere. Inflow is controlled by upstream isolation and plugging so the sewer cannot surcharge while the worker is inside. A trained standby person is stationed at the entry with continuous communication and documented rescue arrangements that do not rely on unplanned entry by others. The entrant wears supplied-air respiratory protection, a retrieval harness and line, and protective clothing against sewage, and hygiene controls and washing facilities are provided, with no eating or drinking until decontaminated. The permit, monitoring and rescue records are retained.
Related legislation
- Model Work Health and Safety Act — primary duty of care; the duty to consult workers; the reckless-conduct offence; and notifiable-incident provisions, as enacted in each jurisdiction.
- Model Work Health and Safety Regulations — Section 291 high risk construction work and the SWMS preparation and review duties, and the confined space provisions where applicable, as enacted in each jurisdiction.
- The relevant plumbing and drainage standards AS/NZS 3500 (Parts 0–5) and, for gas, AS/NZS 5601.1:2022, are called up by the state and territory plumbing and gas safety legislation.
- Plumbing and gasfitting work is licensed under each state and territory's plumbing and gasfitting licensing scheme, with compliance certification required for notifiable work.
- Victoria operates under the Occupational Health and Safety Act 2004 and the Occupational Health and Safety Regulations 2017, with the high risk construction work and confined space provisions applying in place of the model instruments.
Frequently asked questions
Why is sewer and drain work so hazardous?
Entry into sewers and drainage structures combines the confined space itself with the specific hazards of sewers: oxygen-deficient and toxic atmospheres including hydrogen sulphide and methane, biological hazards from sewage, and the risk of sudden inflow or surcharge, all with restricted entry and egress. A confined space in a sewer can be immediately dangerous to life, which is why entry is tightly controlled.
Can sewer work be done without entering the confined space?
Wherever possible, yes — and that is the preferred approach. Inspection and cleaning by camera, jetting and other no-entry methods from the surface eliminate the confined space entry entirely. Entry is only made where it is genuinely unavoidable, and then only under a confined space entry permit with full atmospheric, ventilation, standby and rescue controls.
What atmospheric hazards are present in a sewer?
Sewers can have oxygen-deficient atmospheres, toxic gases such as hydrogen sulphide that can rapidly incapacitate, and flammable gases such as methane. The atmosphere is tested before entry and monitored continuously throughout, with forced ventilation to maintain a safe atmosphere and defined criteria for evacuation if the atmosphere deteriorates.
Why is rescue planning so critical for confined space work?
Many confined space fatalities involve would-be rescuers who enter without controls to help a collapsed worker and are themselves overcome. For that reason, documented rescue arrangements that do not rely on unplanned entry are mandatory: a trained standby person, retrieval equipment, and a rescue plan are in place before entry, so a rescue can be carried out without endangering further workers.
What controls the risk of inflow during sewer work?
Inflow and surcharge are controlled by isolating the structure from inflow where practicable — upstream isolation, plugging, flow diversion or upstream control — so the sewer cannot suddenly fill while workers are inside. The risk of engulfment and drowning is a defining hazard of sewer entry, so inflow control is an essential part of the entry controls.