Where to look first

  • Floor drains, guest showers and laundry sinks that are rarely used and may have dry traps
  • The base of each toilet, where a failed wax seal lets gas escape
  • Under sinks, for loose slip nuts or a missing trap
  • The yard cleanout, for a missing or cracked cap
  • Roof vents, for blockage that lets traps siphon dry
  • Damp spots along walls or floors that could be a drain leak

How traps keep the smell out

Each fixture has a trap that holds a plug of water between the room and the sewer. If the water evaporates, which happens in a shower or floor drain nobody uses for weeks, gas comes straight up. Running water for a few seconds refills it. If the smell returns quickly, the trap may be siphoning because of a vent problem.

Slab-on-grade homes in Placentia have their drain lines under the floor, so a leak in an old cast-iron line can show up as a smell, a damp patch or warped flooring before any water is visible. A persistent odor with no obvious source is worth a camera inspection or smoke test.

A simple home check

  1. Run water in every fixture.Fill each trap, including floor drains and unused showers. Wait a day to see whether the smell is gone.
  2. Rock each toilet gently.A toilet that moves or has water at the base may need a new wax seal.
  3. Check under sinks.Look for drips, loose nuts or a dry trap under bathroom and kitchen sinks.
  4. Check the cleanout cap.Make sure it is on and intact. Do not open it if drains are backing up.

When the smell means more

  • IfSmell plus several slow drainsThenA main line clog may be forming. Limit water use and get it checked.
  • IfSmell plus gurglingThenVents or a partial clog are likely; see the gurgling drains guide.
  • IfSmell plus damp flooring or wallsThenA drain leak is possible. Ask about a camera inspection or leak testing.
  • IfSmell outside near the lateral path with wet groundThenThe lateral may be broken. Keep people and pets away from any wet area.

Questions to ask a plumber

  1. Would a smoke test help find where the gas is getting in?
  2. Are any traps missing or siphoning?
  3. Should we camera the line under the slab?
  4. Would repairs need a permit from the City of Placentia?

Common questions

Is sewer gas harmful?

In a home it is mostly an odor and irritation problem, but it should not be ignored. Persistent or strong odors should be tracked down.

Why does my bathroom smell only when it is windy?

Wind across a roof vent can pull or push air in the system and disturb trap seals. A vent problem is worth checking.

Can a cleaned drain still smell?

Yes. Biofilm in the trap and drain can smell. Cleaning the stopper and trap usually helps.

General information for Placentia, not a quote or professional advice. In an emergency, call 911.