Short answer
A licensed plumber. The three usual causes are a floor waste or fixture trap that has dried out, a perished seal at the base of a toilet pan, and a blocked or missing vent — and the first of those you can rule out yourself in a minute with a jug of water.
What to do before anyone arrives
- Pour a couple of litres of water down every floor waste and every fixture you do not use often — the spare bathroom, the laundry tub. A trap that has evaporated is the most common cause by a wide margin and this fixes it.
- Check whether the smell is worse when it is windy or when the toilet flushes. Both point at venting.
- Look for movement at the base of the toilet when you sit on it. Any rocking means the pan seal is compromised.
- Note where in the house it is strongest and at what time of day.
What to ask when you book
- Will you smoke-test or pressure-test the drainage rather than guessing?
- Is the vent terminating where it should, and is it clear?
- If it is the pan seal, are you replacing the pan connector and re-bedding, or just re-siliconing?
What changes the price
No dollar figures here: this directory holds no price data and an invented range is worse than none. What follows is what makes one of these jobs cost more than the same job next door, which is the part you can actually use when comparing quotes.
- Whether the cause is accessible. A dried trap is free; a broken vent inside a wall is not.
- Whether the drainage has to be opened up to test it.
- Older properties with original venting arrangements that no longer meet current requirements.
What you can do yourself
Is this licensed work?
Licensed plumbing work, including anything involving vents and the sanitary drainage system.
There is no national register. Search the licence number with the regulator for the state the work is happening in.
- NSWNSW Fair Tradingbuilders, electricians, plumbers and specialist trades
- VICBuilding and Plumbing Commission, and Energy Safe Victoria for electricalbuilding practitioners and plumbers; electricians are Energy Safe Victoria
- QLDQueensland Building and Construction Commission (QBCC)building and most trade contractor licences
- WABuilding and Energybuilders, electricians, plumbers and gas fitters
- SAConsumer and Business Servicesbuilding work contractors and supervisors
- TASConsumer, Building and Occupational Services (CBOS)building and occupational licences
- ACTAccess Canberraconstruction occupations licensing
- NTNT Government building practitioner registrationbuilding practitioners and electrical workers
Licensing thresholds and certificate requirements differ by state and change with amending regulation, so this page describes the mechanism rather than quoting a figure. The regulator’s own page is the current answer.
Common questions
- Who should I hire for a smell of sewage in the house
- A licensed plumber. The three usual causes are a floor waste or fixture trap that has dried out, a perished seal at the base of a toilet pan, and a blocked or missing vent — and the first of those you can rule out yourself in a minute with a jug of water.
- Is a sewer smell dangerous?
- Sewer gas is unpleasant well before it is dangerous in a ventilated house, so the practical risk is usually low — but it is also evidence that the barrier between the drain and your house has failed somewhere, and that barrier exists for reasons beyond smell.
Find a Plumber near you
3,553 plumbers in this directory, ranked on published evidence rather than on advertising.
Who to hire for
- Who to hire for a blocked drainA licensed plumber — specifically one who owns a drain machine or a high-pressure water jetter, which not ever…
- Who to hire for a blocked toiletA licensed plumber. Try a proper toilet plunger first — the flanged kind, not the flat cup for sinks — and sto…
- Who to hire for a leaking tapA licensed plumber. It is a small job — usually replacing a washer or a ceramic cartridge — and the useful mov…
- Who to hire for a burst pipeAn emergency plumber, and before they arrive, the water off at the main stop tap. A burst pipe is one of the f…
General information about who does what, not advice about your specific job. Licensing, consumer law and council rules differ by state and change; the regulator for your state is the current source. More guides to hiring a tradesperson.