Plumbing · triage
Sewer or rotten-egg smell in the house
The short answer
First rule out gas: a strong rotten-egg smell in the air near gas appliances or the meter means leave and call. A sewer smell from one drain is most often a dried-out trap: run water into it.
Gas smells like rotten eggs tooUtilities add an odorant to natural gas that smells like rotten eggs. Sewer gas (hydrogen sulfide) smells similar; at high levels it is toxic and you stop smelling it.
Know your shutoffs
Every outcome on this card
Emergency nowIt could be gas
Leave and call from outside.
- Get everyone out
- Don't make a spark
- Call the gas utility or 911 from outside Utilities check suspected leaks for free.
WatchA dry drain trap
Run water to refill it.
- Run water into the drain for a minute The U-shaped trap holds water that blocks sewer gas.
- For floor drains, pour in a bucket of water
- If the smell returns within days, call a plumber
Traps evaporate in drains that go unused for weeks.
This weekA seal or vent problem
Book a plumber this week.
- Check for a loose toilet or a gap at its base
- Ventilate the room
- Call a plumber A failed wax seal, cracked pipe or blocked roof vent are typical.
Related
Written from
Original casaq guidance, updated 2026-10-05. General guidance, not a diagnosis; licensed-pro review pending. Severity levels: Emergency now / Today / This week / This month / Watch. Send a correction.
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