You walk into the guest bathroom — the one nobody uses for months at a time — and the smell hits you. Rotten eggs. Sewage. Something that makes you want to back out of the room and close the door. Or maybe it's more subtle: a faint, persistent odor drifting up from the basement or crawl space that you can't quite pin down.
Sewer gas in your home isn't just unpleasant. It contains methane, hydrogen sulfide, and other compounds that can cause headaches, nausea, and in concentrated amounts, genuine health risks. The good news is that most sewer smell problems have straightforward causes — and once you understand the plumbing mechanics involved, you can often narrow down the source before calling anyone.
The Most Common Culprit: Dried-Out P-Traps
Every drain in your home has a P-trap — that U-shaped pipe underneath the sink, shower, or floor drain. The trap holds a small amount of water that acts as a seal, blocking sewer gas from traveling back up through the pipe and into your living space.
When a drain goes unused for several weeks, the water in the trap evaporates. Once that water seal disappears, there's nothing stopping sewer gas from flowing freely into the room.
This is far and away the most common cause of sewer smell in Fuquay-Varina homes. Guest bathrooms, basement floor drains, utility sinks in the garage, and rarely-used shower stalls are all prime candidates. Homeowners in Bentwinds often mention this issue in upstairs guest suites that sit empty between visitors.
The fix is simple: run water in every drain you don't regularly use, at least once a month. Two cups of water is enough to refill the trap and restore the seal. For floor drains, pour a small amount of mineral oil on top of the water — it floats on the surface and slows evaporation.
Pro Tip: Walk through your house and count every drain — sinks, showers, tubs, floor drains, laundry standpipes, and any other fixture. If you can't remember the last time water ran through one of them, that's your likely source. Run water for 30 seconds to refill the trap.
Wax Ring Failure on Toilets
Your toilet connects to the floor flange (and the drain pipe below) with a wax ring — a thick, pliable gasket that creates an airtight, watertight seal. Over time, wax rings deteriorate. They can crack, compress unevenly, or fail entirely, especially if the toilet has been removed and reinstalled or if it rocks even slightly on an uneven floor.
When the wax ring fails, sewer gas seeps out around the base of the toilet. You might notice the smell is strongest near a particular toilet, or you may see water staining on the ceiling below a second-floor bathroom — a sign that the seal has broken enough to allow both gas and water to escape.
In Lincoln Heights and other established Fuquay-Varina neighborhoods, homes that are 20 to 30 years old are hitting the age where original wax rings start failing. If your toilet rocks at all when you sit on it, the wax ring is almost certainly compromised.
The fix: replacing a wax ring is a manageable DIY project for some homeowners, but it requires removing the toilet, scraping the old wax, and resetting everything properly. If the flange is corroded or broken — common in older homes — the repair gets more complex and typically warrants a professional drain and plumbing assessment.
Damaged or Disconnected Vent Pipes
Your plumbing system has vent pipes that run from the drain lines up through the roof. These vents serve two purposes: they allow air into the system so water flows smoothly (preventing the gurgling sound of a poorly vented drain), and they direct sewer gas safely above the roofline where it dissipates.
If a vent pipe cracks, separates at a joint, or gets blocked (bird nests, leaves, ice in winter), sewer gas can leak into your attic, walls, or living space instead of exiting through the roof. The smell may seem to come from nowhere specific — it just lingers throughout the house.
Fuquay-Varina's older homes, particularly those built before the 1980s, often have cast-iron vent stacks that corrode from the inside out over decades. You may not see any external damage, but the interior walls of the pipe develop pinhole leaks or full cracks that let gas escape into wall cavities. Newer subdivisions like The Park at West Lake and Sunset Ridge use PVC venting, which doesn't corrode but can separate at joints due to settling or improper installation.
When to Call a Pro: If you've checked all your P-traps and the smell persists, the issue is likely in your vent system or the sewer line itself. These require a camera inspection or smoke test to diagnose — both are tools that a plumber brings, not something you can troubleshoot with a flashlight and a YouTube video.
Sewer Line Cracks and Bellies
The main sewer line running from your home to the municipal connection can develop problems over time. Tree root intrusion, ground settling, and pipe deterioration all create openings where sewer gas escapes into the surrounding soil — and from there, into your crawl space or basement.
A common issue in the Fuquay-Varina area is bellied sewer lines — sections of pipe that have sunk due to soil movement, creating a low spot where waste accumulates and generates gas. Clay and Orangeburg pipes, common in homes built before the 1970s, are especially vulnerable.
Signs that your sewer line may be the source include:
- Sewer smell strongest in the basement or crawl space
- Multiple drains running slowly throughout the house
- Gurgling sounds from drains when other fixtures are used
- Patches of unusually green or lush grass in the yard
Less Obvious Sources
A few other culprits worth investigating:
Washing machine drain: The standpipe behind your washing machine has a P-trap that can dry out if the machine isn't used regularly. It can also overflow during drain cycles, pushing water out of the trap.
Ejector pit or sump basket: If your home has a sewage ejector pump (common in homes with basement bathrooms), the pit cover needs to be properly sealed. A missing or cracked cover allows gas to escape continuously.
Water heater anode rod: Sometimes what smells like sewer gas is actually hydrogen sulfide produced by a chemical reaction between your water heater's anode rod and bacteria in the tank. If the smell only occurs when running hot water, this may be the cause — though it's a water heater issue, not a plumbing issue.
When a Smell Becomes Urgent
Most sewer gas situations are nuisance-level problems. But a few scenarios warrant immediate attention:
- Strong smell combined with wet spots or standing water — this suggests an active leak or backup
- Smell accompanied by gurgling in multiple drains — possible main line blockage
- Smell near gas appliances — natural gas (which utilities add mercaptan to for detection) smells similar to sewer gas. If you can't tell the difference, treat it as a gas leak and call your utility company
Frequently Asked Questions
Can sewer gas make you sick?
In typical household concentrations, sewer gas causes headaches, nausea, and irritation rather than serious illness. However, hydrogen sulfide at high concentrations is genuinely dangerous. If the smell is strong enough to cause dizziness or eye irritation, ventilate the area immediately and leave the home.
Why does the sewer smell come and go?
Changes in atmospheric pressure, wind direction, and temperature all affect how sewer gas moves through your plumbing system. A smell that's worse on windy days may indicate a vent pipe issue. A smell that appears in dry weather often points to evaporating P-trap water.
How much does it cost to find and fix a sewer smell?
It depends entirely on the source. Refilling a P-trap is free. Replacing a wax ring runs $150 to $300 with labor. Repairing a cracked vent pipe or sewer line can range from $500 to several thousand dollars depending on accessibility and extent of damage. A professional drain inspection is typically the most cost-effective first step.
Should I pour bleach down the drain to get rid of the smell?
Bleach may temporarily mask the odor but doesn't address the underlying cause. If the issue is a dry P-trap, water is the only fix. If it's a broken seal or cracked pipe, no amount of chemical treatment will solve the problem. Focus on identifying the source rather than covering up the symptom.
Is sewer smell covered by homeowners insurance?
Generally, homeowners insurance does not cover the repair of deteriorated or aging plumbing components. However, if a sudden sewer backup causes property damage, the cleanup and restoration may be covered under certain policies. Check your policy for sewer and water backup coverage, which is often an add-on endorsement.
