What Causes a Sewage Smell in Your House? And What to Do About It

That warm, clean, and welcoming house you love to come home to? Well, nothing ruins the good vibes like a sewage smell. It’s the kind of thing that makes you want to cancel hosting the weekly game night or book club until you figure out what’s going on.

Whether the smell is coming from a drain, the bathroom, or somewhere you can’t quite pinpoint, the good news is that sewer odors are usually fixable. But while you may be able to handle some odor issues on your own, others are best left to professionals.

Key Takeaways

A sewage smell in your home can come from several sources, including dry P-traps, blocked vents, cracked pipes, and sewer line issues.
Some causes are simple to address on your own, but persistent or widespread sewer smells often point to a bigger problem needing professional attention.
Left unaddressed, sewage odors can signal issues that lead to costly repairs or may pose health risks to your household.
Preventing sewer odors starts with regular home maintenance, like routinely running water in guest bathrooms and scheduling professional inspections.

Identifying a Sewage Smell in Your Home

Let’s be honest, a sewer smell in your house is hard to miss. It’s a distinct odor of sulfur or rotten eggs. It often seems to come out of nowhere, then it just hangs in the air.

The smell comes from sewer gases, which include hydrogen sulfide and other byproducts that build up in your plumbing system. A sewage smell can pop up in the bathroom, kitchen, basement, or even a room with no obvious plumbing nearby.

If you’re wrinkling your nose when you enter a certain room or area of your house, it’s likely a sewer gas odor.

When to Call in the Professionals

A sewer odor in your house is more than just unpleasant. It can be a real health risk. Sewer gas contains hydrogen sulfide. According to the CDC, this toxic gas can cause headaches, dizziness, and nausea even at low levels.

Sewer gas also contains methane, which is odorless and highly flammable, creating a potential fire hazard in your home.

That’s why you shouldn’t let sewer smells hang around for too long. Call for professional help right away if you notice:

The smell is strong, sudden, or getting worse quickly.
Multiple drains in your home smell at the same time.
You or anyone in your household is experiencing headaches, nausea, or dizziness.
You hear gurgling sounds from pipes or see sewage backing up.
You’ve tried basic fixes, and the sewer smell keeps coming back.
You suspect you have a cracked pipe or a damaged sewer line.

Sewage Smell Causes

Sewer odors in your house don’t always come from one obvious place. It can be tricky to track down the source. Here are the most common culprits, broken down by area. Follow your nose, then choose the appropriate fix.

Sink Drains

Your kitchen and bathroom sinks are two of the most common sources of sewer smells in the house. Here’s why:

Dry P-trap: The P-trap is that curved pipe under your sink that holds a small amount of water. That water acts as a barrier to block sewer gases from coming up through the drain. If a sink goes unused for a while, the water evaporates, and the barrier disappears.
Buildup in the drain: Grease, food particles, soap scum, and other debris can collect in your drain over time and start to smell.
Blocked or damaged vent pipe: Your plumbing system uses vent pipes to release sewer gases outside. If a vent gets blocked by debris, those gases have nowhere to go but back into your home.

Try running water in sinks you don’t often use to keep the P-trap full. For a buildup, try pouring a mixture of baking soda and vinegar down the drain, then run hot water. If the smell keeps lingering, call a professional plumber to inspect your vent pipes and clear any blockages.

Toilets

A toilet that smells like sewage is hard to ignore. There are a few reasons it might be happening:

Dry or damaged wax ring: The wax ring seals the base of your toilet to the floor and keeps sewer gases from escaping. Over time, it can dry out, crack, or shift, especially if the toilet rocks.
Dry P-trap: Just like with sinks, toilets in guest bathrooms that aren’t used regularly can develop dry P-traps.
Buildup inside the toilet: Bacteria and mineral deposits can build up under the rim and inside the bowl, creating an ongoing odor.

Remember to flush toilets in unused bathrooms regularly to keep P-traps full. Clean inside the bowl and under the rim with a toilet cleaner to remove buildup. A rocking toilet or an ongoing sewage smell in the house near the toilet base likely means the wax ring needs to be replaced. This is a job for a professional plumber.

Shower and Bathtub Drains

Shower and tub drains collect a lot of hair, soap, and skin cells over time. That buildup creates the perfect environment for bacteria to grow and odors to develop. The odor can also be coming from a dry P-trap in the showers or tubs in less-used guest bedrooms.

To prevent smells, run the shower periodically in bathrooms that don’t get much use. Remove and clean the drain cover and use a drain snake or hair catcher to pull out any buildup. For stubborn clogs, call a professional to perform a thorough cleanup of the drain and surrounding pipe.

Basement Floor Drains

Floor drains in basements and utility rooms are easy to forget about. They aren’t used \very often. That makes them a prime spot for a dry P-trap and sewer gas backup.

Pour water down the floor drain every few months to keep the P-trap full. You can also add a small amount of mineral oil, which evaporates more slowly than water and helps maintain the seal longer.

Sewer Line Problems

A sewage smell in the home can point to something bigger than a dry drain or dirty pipe. A cracked, damaged, or blocked sewer line can allow sewer gases to seep into your home. That’s not something you can afford to ignore.

Signs of a sewer line issue include:
Bad smells coming from multiple drains
Water draining slowly from multiple drains
Gurgling sounds in your pipes
Sewage backup in your home

Sewer line issues aren’t a DIY fix. If you think you have a problem with your main sewer line, call a professional right away. A trained technician can inspect the line, identify the damage, and safely handle the sewage cleanup before the problem gets worse.

Ways to Prevent a Sewage Smell in Your House

The best way to deal with sewer odor in your house is to keep it from showing up in the first place. A little routine maintenance goes a long way:

Run water in your unused drains regularly: Guest bathrooms, basement floor drains, and any other fixtures that don’t see regular use are prime spots for dry P-traps. Make it a habit to run water in these areas every few weeks to keep the seal intact.
Clean your drains on a regular schedule: Hair, grease, and soap buildup are some of the biggest contributors to drain odors. Perform a monthly flush with baking soda and hot water to help keep things fresh and flowing.
Check your toilet seals: A rocking or loose toilet can wear down the wax ring over time. If you notice any movement at the base, call a plumber before it becomes a bigger problem.
Schedule routine plumbing inspections: A professional plumber can spot early signs of trouble, like a cracked pipe or a blocked vent, before they turn into a sewage smell in your house. An annual checkup is a smart investment.
Keep an eye on slow drains: A drain that’s moving slowly is often a warning sign. Address the clog early to prevent the kind of buildup that leads to a persistent sewer smell in the house.

How to Get the Sewer Odor Out of Your House

Once you’ve tracked down and fixed the source of the problem, you may still notice a lingering sewage smell in your house. That’s normal. Sewer gases can cling to soft surfaces and stay in the air even after you’ve resolved the root cause. Here’s what you can do:

Ventilate your home: Open windows and doors to let in fresh air and push out the stale air. Run ceiling and exhaust fans to help move the process along.
Wash soft surfaces: Curtains, rugs, towels, and upholstered furniture can absorb odors. Washing or steam cleaning these items can make a noticeable difference.
Clean the affected area: Wipe down walls, floors, and surfaces near the source of the smell with a household cleaner or a diluted white vinegar solution. Give extra attention to the area around drains and the base of toilets.
Use baking soda: Sprinkle baking soda on carpets and upholstered surfaces. Let it sit for a few hours and then vacuum it up. Baking soda is a natural odor absorber and works well on lingering smells.
Add an air purifier: An air purifier with an activated carbon filter can help remove lingering odor particles from the air.

If the smell sticks around even after cleaning, that could mean you haven’t fully fixed the source of the issue. At that point, it’s time to call in a professional.

Say Goodbye to Sewage Smell

After a long day of work, the last thing you need is to come home to a stinky house. Shoving an electric air freshener into a wall outlet isn’t the right solution. In fact, if you let the sewage smell linger, it could put your family’s health at risk. A sewer smell may also signal damage that gets more expensive to fix the longer you wait.

You don’t have to fight bad odors alone. SERVPRO specializes in sewage cleanup. Our train professionals are available 24/7 to assess your unique situation, identify the source of the odor, and make it “Like it never even happened.”

Contact your local SERVPRO today.

FAQs

Why does my house smell like a sewer?

A sewer smell in your house is usually caused by a dry P-trap, a blocked or damaged vent pipe, a cracked sewer line, or buildup in your drains. The first step toward fixing the problem is identifying which drain or fixture the smell is coming from.

What causes a sewer smell in a house?

The most common causes of a sewer smell in a house include dry P-traps, clogged or dirty drains, damaged wax rings around toilets, blocked vent pipes, and cracked sewer lines. Each of these issues allows sewer gas to escape into your living space.

What does sewer gas smell like?

Sewer gas smells like rotten eggs or sulfur. That distinct, unpleasant odor comes primarily from hydrogen sulfide, a gas that forms as organic matter breaks down in your plumbing system. If you notice that smell in your home, it’s important to figure out the source right away.

How do I get rid of a sewer gas smell?

To get rid of a sewer gas smell, start by figuring out the source. Run water in unused drains to refill dry P-traps, clean buildup from drains, and check toilet seals. If the smell is still around after these fixes, call a professional plumber to check out your system.

What Causes Sewage Smell in Your House?