Why Does My House Smell Like Sewage Sometimes?
Last updated October 26, 2026
The short answer
Dried-Out P-Traps
The curved pipe under every sink and floor drain holds a small amount of water that blocks sewer gases from rising into your home. When that water evaporates, especially in a guest bathroom or a floor drain you rarely use, the smell slips through. This is often the easiest issue to fix yourself.
Run water into every sink, tub, and floor drain for about 30 seconds. If the odor disappears, the P-trap was the culprit. To keep it from happening again, pour a cup of water down unused drains every couple of weeks. In coastal areas with high humidity, this is less common, but it still happens in spare bathrooms.
Cracked Vent Pipes
Your plumbing system includes vent pipes that run up through the roof, letting sewer gases escape outside and allowing water to flow freely. A crack or loose joint in one of these pipes can release gases into your attic or wall cavity, which then drift into living spaces. The smell often worsens after heavy rain or when the wind blows a certain direction.
Check your attic for any visible pipe damage or stains. If you spot a problem, a plumber can repair the vent pipe. This is not a job for a water damage pro, but if the crack has caused water damage to your ceiling or walls, you may need both a plumber and a restoration specialist.
Toilet Base Leaks
A loose or failing wax ring under your toilet can let sewer gas escape around the base, and it may also allow small amounts of water to seep out. The smell might be strongest right after someone flushes. Check for water stains or a wobbly toilet, which are signs the seal has broken.
Tightening the toilet bolts can sometimes help, but if the wax ring is damaged, it needs replacing. This is a straightforward plumbing job. If you notice water damage on the floor or subfloor, you may need water damage pros to dry and repair the area after the plumber fixes the seal.
Slow Drain Blockages
When a drain is partially clogged, wastewater sits in the pipe and can release a sewage-like odor. The smell may come and go as water slowly moves through. Hair, soap scum, or food particles often cause these blockages. You might notice gurgling sounds when you flush or run water.
Try clearing the drain with a plunger or a drain snake. Avoid chemical cleaners, as they can damage pipes. If the clog persists, a plumber can clear it. If the blockage has caused water to back up and soak your floors or walls, you may need sewage cleanup services to handle the mess safely.
When to Call the Pros
If you cannot find the source of the smell, or if it comes with visible sewage backup, do not wait. Sewage contains bacteria that can harm your health, so see a doctor if you feel unwell. A professional can inspect your plumbing and identify the exact cause of the odor.
For sewage backup cleanup, local water damage pros have the equipment to remove contaminated water and disinfect affected areas. They can also dry out materials to prevent mold growth. If you live in Virginia Beach, keep your shutoff valve location written down in case you need to stop water flow quickly.
- Check P-traps in unused drains first
- Look for water stains around the toilet base
- Listen for gurgling sounds in drains
- Inspect attic vent pipes for cracks
- Avoid chemical drain cleaners
- Act quickly if sewage backs up
Water damage does not wait
Phones are answered 24/7 for Virginia Beach and nearby communities.
Call Now (757) 665-2121Frequently asked questions
Why does the sewage smell come and go?
Intermittent odors often mean a P-trap is drying out or a vent pipe has a small crack. The smell may intensify with wind or rain. Check the simplest causes first, like running water in unused drains.
Can a sewage smell be dangerous?
Sewer gas contains methane and hydrogen sulfide, which can cause headaches or nausea at low levels. If you smell it constantly, it can be a health risk. See a doctor if you feel unwell, and address the source quickly.
What should I do if I see sewage backup?
Stop using water in that area and avoid contact with the sewage. Open windows for ventilation. Then call the pros who handle sewage cleanup. They can remove the waste and disinfect the area safely.
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