Why does my house smell like sewer?
Sewer gas is reaching living space through a gap that should be sealed. Every drain holds a water plug in its trap to block that gas. When the water evaporates, a seal fails, or a vent blocks, the gas takes the easiest path — which is into the room.
The smell itself is not the problem; it is the symptom of a broken barrier. Masking it with a drain cleaner or an air freshener leaves whatever failed still failing.
What is a dry trap and how do I fix it?
A trap is the U-bend under every drain, holding water that blocks sewer gas. If a fixture goes unused for weeks the water evaporates and the barrier disappears. Running the tap for thirty seconds refills it and the smell usually goes within the hour.
This is the most common cause and the cheapest fix, so it is worth ruling out first. Likely candidates are a guest bathroom, a basement shower, a utility sink, or a floor drain in a garage that never sees water.
For a floor drain that dries out repeatedly, a cup of water every few weeks maintains the seal. A trap primer is the permanent version if the drain matters.
Why does the smell come from the toilet?
Usually a failed wax ring — the seal between the toilet base and the flange in the floor. When it degrades, gas escapes around the base. A toilet that rocks slightly when you sit on it is the classic accompanying sign.
A failed wax ring often leaks a small amount of water as well, soaking subfloor quietly for months before anything shows on the surface. If the flooring around the base has softened or discoloured, that is what has been happening.
Can a blocked vent cause a sewer smell?
Yes. The vent stack lets air into the drain system so water can flow without siphoning traps dry. If it blocks — a nest, debris, or ice in a Bend winter — draining fixtures pull the water out of nearby traps and the gas follows.
The tell is a smell that appears after you use a fixture rather than constantly, often accompanied by gurgling from a different drain. Ice at the top of a vent stack is a genuinely seasonal cause here and clears itself as the weather warms, which can make it look intermittent.
When does a sewer smell mean a damaged line?
When it persists after every trap is filled and the toilets are sealed, when it is strongest in a crawlspace or basement, or when it comes with slow drains across several fixtures. That combination points at the drain line rather than a fixture.
In Bend the older core around Downtown, Old Bend, the Orchard District and River West still runs vitrified clay and cast iron, both of which separate at joints as the ground moves through a freeze-thaw season. A cracked or offset section leaks gas long before it causes a visible backup.
A camera run is what settles it. If you have worked through the traps and the smell is still there, a drain camera inspection shows whether the pipe itself is the source — and if it is, sewer line cleaning or a repair is the next step depending on what the footage shows.
Is sewer gas in the house dangerous?
At the concentrations most homeowners notice it is an irritant rather than an acute hazard — headaches, nausea, irritated eyes. It is also flammable at high concentrations and a reliable sign that something in the drain system has failed.
Treat a persistent smell as a fault to find rather than a nuisance to tolerate. Ventilate the room, work through the traps, and if it is still there, get the line looked at.
Last reviewed 2026-09-21 by Bend Plumbing Pros, Bend, OR.