Short answer
Most sewer odors come from a dry drain trap, a failed toilet wax ring, a blocked or cracked vent pipe, or a leaking or cracked drain line. Pour water into rarely used drains first. A persistent smell with slow drains or gurgling points to a blockage or broken pipe.
Check these first
- Run water in guest baths, floor drains and basement sinks to refill dry traps
- Look for movement or water around toilet bases (wax ring)
- Clean the overflow hole in bathroom sinks
Call a plumber when
- The smell comes with slow drains or gurgling
- You smell sewage in the yard
- The odor is strongest in a wall or ceiling
- There's any sign of backup
Find the source by where you smell it
| Where | Likely cause | Fix |
|---|---|---|
| Rarely used bathroom or floor drain | Dry P-trap | Run water for 30 seconds |
| Around a toilet base | Failed wax ring | Reset the toilet with a new seal |
| Laundry area | Washer standpipe trap or venting | Plumber check of trap and vent |
| Whole house, worse on windy days | Blocked or cracked vent | Inspect roof vent |
| Yard or crawl space | Cracked sewer line or loose cleanout cap | Camera inspection |
When sewer smell is a safety issue
Sewer gas contains hydrogen sulfide and methane. A faint, occasional smell from a dry trap is a nuisance; a strong, constant smell needs attention. If you smell a rotten-egg odor near a gas appliance, it may be natural gas instead: leave the house and call 911 or the gas utility before anything else.
When to call a plumber
If the steps above don't solve it, or anything involves sewage, gas, electricity near water or a leak you can't stop, call a licensed plumber. Related help: drain cleaning in Gastonia, sewer line repair in Gastonia, toilet repair in Gastonia.
Where this comes up most in Gaston County: Willow Creek, York-Chester, Loray Mill Village, Downtown Gastonia, Forest Heights, Highland, Belmont, NC, Mount Holly, NC. See all Gastonia and Gaston County service areas.
Frequently asked questions
Why does my drain smell like sewage?
Often a dry or partially clogged trap, or buildup in the drain. If it persists with slow drainage, there may be a vent or drain line problem.
Editorial note: this guide gives general safety and maintenance information for homeowners. It doesn't replace an on-site diagnosis by a licensed plumber. Codes and permit rules can change; check with your local inspections office.