Plumbing tips · October 23, 2026
The smell that haunts one bathroom
When only one bathroom smells like sewer, the cause is usually in that room. Start with the simplest one, because it is often the answer.
A drain nobody uses
Every drain has a trap that holds a little water, and that water is what keeps sewer gas out of the house. A guest shower, a tub or a floor drain that never gets used slowly dries out, and the smell comes straight up. Run water down every drain in that room for a minute and see if the smell fades over the next day.
The seal under the toilet
A toilet sits on a wax ring that seals it to the drain. If the toilet rocks, or the ring has failed, sewer gas can leak out around the base. A smell strongest at the floor by the toilet, or a stain around its base, points here.
The sink overflow
The small overflow hole near the top of a bathroom sink collects soap scum and grime over time, and it can smell like a drain. Cleaning it out is worth trying before anything else.
A vent problem
Drains need air from a vent through the roof to work right. If that vent is blocked, draining water can pull the water out of the traps, and the smell comes back again and again. Gurgling drains along with the smell are the clue.
Questions we get asked
Is sewer gas dangerous?
A faint smell is mostly unpleasant, but sewer gas should not be in a home. A strong or constant smell is worth having traced, and a smell like rotten eggs near a gas appliance should be treated as a possible gas leak.How often should I run water in an unused drain?
Running water for a minute every couple of weeks keeps the trap full. Drains in a guest bath are the usual ones that dry out.Why does the smell come and go?
A trap that is drying out, or a vent that is partly blocked, can let the smell through only some of the time, often after a lot of water has drained somewhere else in the house.Plumbing questions we answer
Where we go
Parker, Wise and Tarrant County, out of the shop in Springtown. Springtown, Weatherford, Azle, Boyd, Decatur, Newark, Millsap, Fort Worth and the country in between.
Call 817-487-8866