Sewage Smell in House? 6 Plumbing Causes and How to Fix Them

Dry P-traps

A drain that has not been used in weeks — a guest bathroom, a basement floor drain — loses the water in its trap and lets sewer gas through. Run water for a minute and see if the smell clears.

Failed toilet wax ring

If the smell is strongest near a toilet that rocks or has water at the base, the wax seal has failed. This is a quick toilet repair.

Blocked plumbing vent

Vent stacks on the roof can clog with leaves or nests, causing gurgling drains and sewer odors inside. A plumber can clear the vent.

Cracked or broken sewer line

A persistent sewage smell — especially outdoors or in the basement — often means a damaged sewer line. A sewer camera inspection shows the problem, and sewer line repair fixes it before it becomes a sewer backup.