A persistent sewage or rotten-egg smell near a drain, toilet or floor waste may indicate sewer gas entering through a dry trap, failed fixture seal or drainage vent fault. Localised odour, gurgling and slow drainage support a plumbing cause, but smell alone cannot confirm the source.
Recurring sewage odour can be one of the signs of a wider plumbing problem. A licensed plumber may need to distinguish a simple dry trap from a concealed drainage defect.
What signs should you check?
Without opening or dismantling anything, note whether the smell:
- is strongest near a floor waste, sink, shower, toilet or laundry fixture
- comes from a drain that is rarely used
- returns after the room has been aired
- occurs with gurgling or slow drainage
An unused fixture may have a dry trap. A trap holds a water seal that limits foul air entering from the sanitary drainage system. If drains are also noisy, check what gurgling drains can indicate.
How do you get rid of the odour safely?
For an accessible sink, shower or floor drain that has not been used recently, run clean water briefly to refill the trap. If the smell disappears and does not return, evaporation from an unused trap may have been the cause.
Leave the area and arrange an inspection if the odour remains strong, persists or returns. Do not dismantle fixtures or pipework, open walls, enter confined spaces or climb onto the roof to inspect vents.
A plumber can inspect fixture seals, traps, drainage and venting. If the source is concealed, they may use controlled smoke testing or another appropriate diagnostic method to locate the escape point. The lasting repair may involve restoring a trap seal, repairing a fixture connection, clearing a drainage fault or correcting venting.
When should you leave immediately?
If the smell could be fuel gas, go outside immediately. Do not use electrical switches, flames or cigarettes, and do not try to locate or test the leak. Follow the steps for responding safely to a suspected gas leak. From a safe place, call the gas distributor’s emergency number, or call 000 if there is immediate danger. Once the immediate risk is addressed, arrange licensed gas leak detection if the fault is within the property.
If a strong unknown odour causes headache, nausea, dizziness or irritation, move into fresh air and call the Poisons Information Centre on 13 11 26 for advice. Call 000 for collapse, severe breathing difficulty or serious illness.
If sewer odour persists or returns, contact Fixed Today for licensed drain and vent diagnosis. Our plumber can locate the source and repair the underlying fault rather than masking the smell.