Why Does My House Smell Like Sewer Gas?

A sewer gas odor in your home is more than unpleasant, it can be a health and safety concern. Sewer gas contains methane and hydrogen sulfide. If you smell it, here's what's likely happening.

Common causes

• A dried-out P-trap in a rarely used drain
• A damaged or blocked plumbing vent
• A cracked or loose toilet seal
• A break in the sewer line
• A clogged drain trapping gas

The easy fix to try first

If the smell comes from a seldom-used sink, shower, or floor drain, the water in the P-trap may have evaporated. Simply running water to refill the trap often solves it, since that water blocks gas from rising.

When it's serious

If refilling traps doesn't help, the problem may be a venting issue, a failed toilet seal, or a sewer line break, all of which need professional attention.