Symptoms
- Smell noticeable near the toilet even when clean
- Smell worse after flushing or in humid weather
- No visible leak but odor persists
- Smell may come and go
Likely causes
- CommonDry trap from infrequent useThe water seal in the trap evaporates in a rarely used bathroom, letting sewer gas rise up.
- CommonFailed wax ring seal at the baseA broken wax ring lets sewer gas escape around the base of the toilet.
- PossibleCracked or loose caulk seal at the floorGaps between the toilet base and floor let odor seep out even without a water leak.
- PossibleVenting problem allowing gas to back upA blocked or poorly designed vent stack can push sewer gas back through fixtures.
What to do
- Flush the toilet a few times to refill the trap if it's been sitting unused, and see if the smell clears.
- Check for water around the base or a rocking toilet, which points to a wax ring issue.
- Inspect and reseal any cracked caulk around the toilet base, leaving a small gap at the back for potential future leak detection if your area code requires it.
- Check the tank bolts and any other visible connections for leaks that could indicate a bigger sealing problem.
- If the smell persists with no visible leak, consider that the wax ring may need replacing, which requires removing the toilet.
Tools and parts
- Caulk and caulk gun
- Flashlight
Toilet wax ringSearch: “toilet wax ring seal replacement”
When to call a pro
Call a plumber if flushing regularly and resealing the base doesn't fix it, since the wax ring or venting may need professional attention.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.