Sewer smell in your house? Here is what it usually is
A sewer smell inside the house feels alarming, but the cause is usually small. Sewer gas is supposed to stay in the pipes, held back by water seals and vented out the roof. When you smell it, one of those barriers has failed. Here are the usual suspects, in the order I check them.
The dry trap, the most common cause
Every drain has a P-trap, the U-shaped bend that holds water and blocks gas. If a fixture sits unused for weeks, that water evaporates and the smell walks right in. Guest bathrooms, laundry sinks, and the floor drains some Charlotte garages and utility rooms have are the classic offenders.
The fix is free. Pour a quart of water down every rarely used drain. Add a spoon of cooking oil on top and it evaporates slower. If the smell fades in a day, you are done.
The wax ring under a toilet
A toilet seals to the floor with a wax ring. When it fails, gas seeps out around the base, and you often notice the toilet rocking slightly too. A new ring with reset runs about $150 to $250 as part of a fixture visit. Left alone, the leak rots the subfloor, and on a crawl space home that damage spreads out of sight before anyone smells trouble.
Vents and bigger problems
Your drain system breathes through a vent stack on the roof. When leaves or a bird's nest cap it, gas gets pushed back through the traps, sometimes with a gurgling sound as the tell. Charlotte's tree canopy makes leaf-blocked vents a genuinely common find. And if the smell is strongest outside or in the yard, the sewer lateral itself may be cracked. That is when a camera inspection earns its $150 to $300. Persistent smells that survive the water trick deserve a professional look.
When to stop sniffing and call
Call if the smell is strong and constant, if multiple drains gurgle when the washer runs, or if the yard smells worse than the house. Those point at the main line, not a dry trap. Describe what you notice and where, and I can usually tell you over the phone which of these you are dealing with before anyone drives over.