Treat sewage and human faeces as potentially infectious contamination. Keep people and pets away, stop the inflow only if it is safe, and contact a licensed plumber. Do not start cleaning until the source has stopped and electrical, gas and structural hazards have been ruled out. Understanding what causes sewage to back up can help distinguish a private drainage fault from a wider wastewater problem.
Health risks and immediate precautions
Sewage exposure can cause gastrointestinal illness and skin or eye infections, particularly when contamination reaches the mouth, eyes or broken skin. Blocked drains can also create health hazards before an overflow becomes obvious.
Do not enter if sewage may have contacted electrical wiring, appliances or gas equipment. Do not operate switches or equipment; arrange clearance from a licensed electrician or gasfitter. If there is an immediate danger or you smell gas, leave the property and call 000 from a safe location.
For a minor clean-up that a plumber or remediator has confirmed is safe to handle, wear waterproof gloves and boots, eye protection, and washable or disposable protective clothing. Cover cuts with waterproof dressings. Keep children, pets and immunocompromised people away.
Avoid pressure washing, dry sweeping or anything that creates splashes or mist. A standard face mask does not make a widespread or aerosol-producing clean-up safe.
Wash exposed skin promptly with soap and clean water. Rinse splashed eyes with clean running water. Seek advice from Healthdirect or a doctor after significant exposure, contamination of a wound, or symptoms such as vomiting, diarrhoea, fever or worsening irritation. Call the Poisons Information Centre on 13 11 26 for disinfectant exposure.
How to clean a small, contained backup
Make the area safe: Start only after the sewage inflow has stopped and any electrical, gas and structural hazards have been cleared. Prevent contamination being tracked into unaffected rooms.
Remove sewage and debris: Use disposable absorbent material and work gently to minimise splashing. Do not use an ordinary household or wet-and-dry vacuum, as it may become contaminated and spread droplets.
Remove unsalvageable porous materials: Saturated carpet underlay, insulation, plasterboard and particleboard generally cannot be reliably cleaned and dried throughout. Securely contain contaminated waste and check your council’s disposal requirements. Do not cut or disturb materials that may contain asbestos; arrange an asbestos assessment if uncertain.
Clean hard surfaces: Wash intact, non-porous surfaces with detergent and clean water. Removing organic matter is essential because it can reduce disinfectant effectiveness.
Disinfect: Use a product suitable for the surface and follow its Australian label for dilution, ventilation, application and wet contact time. Never mix bleach with ammonia, acids or other cleaners because toxic gas may form. Stronger solutions are not necessarily safer or more effective.
Dry completely: Dry cleaned surfaces promptly without directing contaminated air into unaffected areas. Sewage or moisture beneath floors, inside walls or in ventilation systems requires professional remediation.
Finish safely: Clean reusable tools, remove protective equipment without touching contaminated surfaces, contain disposable items and wash your hands thoroughly.
When professional help is needed
Use a specialist remediator if contamination is widespread, involves porous building materials, has entered concealed cavities or ventilation, or cannot be safely dried. Never enter drains, pits, crawlspaces or other confined spaces.
An appropriately licensed plumber must repair private drainage faults. Learn how to recognise and report a blocked public sewer if the overflow may originate from Sydney Water’s wastewater network.
If sewage is still entering your property, keep clear and contact our licensed sewage and blocked sewer plumbers to isolate and repair a private drainage problem. Seek medical advice after significant exposure or if symptoms develop.