Dry P-traps
Every drain has a water-filled trap that blocks sewer gas. A guest bathroom or floor drain that isn't used for weeks dries out and lets gas in. Run water for a minute and the smell often disappears.
Failed wax ring or loose toilet
A toilet that rocks or has a broken seal lets gas escape at the base. It also leaks water into the subfloor. Resetting the toilet with a new wax ring fixes both.
Blocked or damaged vent stack
Plumbing vents on the roof let sewer gas out and air in. A bird nest, leaves or a crack in the vent pipe can push gas back into the house.
Cracked or backed-up sewer line
If the smell is persistent, strongest in the basement or yard, and comes with slow drains or gurgling, the main sewer line may be cracked or blocked. A camera inspection pinpoints it. Note: if you smell sulfur near a gas appliance, treat it as a gas leak and leave the house.
Need a plumber for this?
MGA Plumbing provides sewer line repair 24/7 in every Missouri city — Kansas City, St. Louis, Springfield, Columbia and hundreds more. Upfront pricing, same-day service. Call (888) 480-9811.