How to Get Rid of Sewer Smell in Your House
Short answer
Sewer gas gets into a house when the water seal in a drain trap disappears, most often in a floor drain, spare shower, or guest sink that's rarely used. Pour water down every drain to refill the traps. If the smell comes back, look for a loose toilet, a dirty sink overflow, a leak, or a blocked plumbing vent. If several drains smell at once, call a plumber. If it smells like rotten eggs and you have gas appliances, leave and call your gas company.
Quick steps
- If you smell rotten eggs and have gas appliances, leave the house and call your gas company first.
- Run water down every drain for a few seconds, especially floor drains and spare bathrooms.
- Clean the sink overflow hole with a small brush and hot soapy water.
- Check that toilets don't rock and there's no water around their base.
- Fit a trap seal on floor drains that keep drying out, and call a plumber if the smell persists.
Need supplies? Jump to what to buy
First: is it gas?
Natural gas has a rotten-egg smell added so leaks are noticed, and sewer gas can smell much the same. If you have a gas stove, furnace, or water heater and the smell is strong or near those appliances, leave the house and call your gas company from outside. Don’t flip switches or light anything.
Why sewer smell gets in
Every sink, tub, shower, and floor drain has a curved pipe under it called a trap. The water sitting in the bend blocks gas from the sewer. If that water evaporates, gas comes straight up the drain. North Dakota’s Department of Environmental Quality says sewer gas in homes is usually caused by a dry trap in a rarely used drain or by leaks in the plumbing.
1. Refill the traps
Run water for a few seconds in every drain in the house:
- Floor drains in the basement, laundry room, and garage
- Spare showers, tubs, and guest sinks
- Utility sinks and any drain near the water heater
Most of the time the smell is gone within an hour. If a drain is rarely used, run water in it every couple of weeks. For floor drains that keep drying out, a waterless trap seal lets water down but stops gas coming up.
2. Clean the sink overflow
The small hole near the top of a bathroom sink collects soap scum and gunk, and it can smell like sewage. Scrub inside it with a small bottle brush and hot soapy water, then pour hot water through it.
If a sink drain smells of rot rather than sewage, the cause is usually gunk in the drain itself. See how to clean a smelly drain.
3. Check the toilets
A toilet sits on a wax ring that seals it to the drain pipe. If the toilet rocks, or there’s water or staining around the base, the seal may have failed and gas can escape. Resetting a toilet on a new wax ring is a common DIY job, but call a plumber if you’re not sure.
4. Look for leaks and the vent
Drain pipes are connected to a vent pipe that comes out through the roof. If the vent is blocked by leaves or a bird’s nest, drains can gurgle and traps can be sucked dry. Also look under sinks for wet cabinets or loose pipe joints.
When to call a plumber
Call a plumber if:
- The smell comes from several drains at once, which points to the main sewer line or vent
- Drains gurgle or empty slowly throughout the house
- The smell comes back after you’ve refilled every trap
- You see sewage or water around a toilet, floor drain, or in the yard
If the smell is more like urine than sewage and it’s strongest around the toilet, see how to get rid of urine smell in a bathroom. If it smells sweet and rotten, like spoiled meat, and it’s strongest at one wall, ceiling, or vent rather than a drain, it’s more likely a dead animal smell.
What to buy
We may earn a commission if you buy through these links, at no extra cost to you. How this works
Waterless floor drain trap seal
Waterless Trap Seal for 2 inch drains
Floor drains and rarely used drains that keep drying out and letting sewer gas in. A one-way valve lets water down and stops gas coming up.
Good to know: Measure the drain pipe before you buy. If several drains smell at once, the problem is probably the vent or sewer line, not one trap.
Check price on AmazonCommon questions
How do you eliminate sewer odor in a house fast?
Run water for a few seconds in every drain, including floor drains and spare showers, to refill the traps. That fixes most sewer odor within an hour. If it doesn't, open windows, then check toilets for a failed seal and clean the sink overflows.
Why does my house smell like sewage but the drains are fine?
Look at the toilets, the sink overflows, and any floor drain you forgot, then check outside for a blocked roof vent. If the smell is more like rotting meat and sits in one wall or ceiling spot, it may be a dead animal instead.
Is sewer gas dangerous?
A faint smell from a dry trap is mostly unpleasant. Sewer gas contains hydrogen sulfide, which can irritate the eyes and cause headaches or nausea at higher levels. If the smell is strong or anyone feels unwell, air out the house and call a plumber.
Why does my bathroom smell like sewage only sometimes?
A trap that dries out between uses, a vent that's partly blocked, or wind pushing air down the vent can all cause a smell that comes and goes. Running water in rarely used drains every couple of weeks often fixes it.
How is natural gas different from sewer smell?
Gas companies add a chemical that smells like rotten eggs, which is close to how hydrogen sulfide in sewer gas smells. If you have gas appliances and smell rotten eggs, treat it as a gas leak: get out and call the gas company from outside.
Will a sewer smell go away on its own?
If it came from a dry trap, it goes once you run water to refill it. If it keeps coming back, something is wrong, like a cracked pipe, a failed toilet wax ring, or a blocked vent, and it won't fix itself.
Who should I call for a sewer smell in the house?
A plumber. If sewage has backed up into the house, also call a water damage cleanup company, because soaked materials need to be removed.