Walked into your home and been hit with the smell of rotten eggs or sewage? A strong sewage smell in the house is often the first clue that something’s off with your septic system.And when those smells show up inside, not outside, it’s often a sign of a more serious issue.
Septic smells indoors usually mean something’s going wrong with your drains, vents, or the tank itself. Ignoring it can lead to plumbing backups, health risks, or costly damage.
In this guide, we’ll break down the 10 most common reasons your septic tank smells inside your home, what each one means, and how to fix the problem before it gets worse.
Dry P-traps
If you smell a sewer-like odor from a sink or shower you rarely use, a dry P-trap might be the cause. A P-trap is that curved pipe under your sink, tub, or floor drain. It holds a small amount of water to block gases from rising up through the pipes.
When a sink or tub goes unused for a while—like in a guest bathroom or basement—the water in the P-trap can dry up. Once it’s gone, nothing’s stopping hydrogen sulfide or methane gas from coming into your home.
The fix is simple: just run water down the drain for about 30 seconds to refill the trap and restore the barrier.
Blocked or damaged vent pipes
Your home’s plumbing vents might not look like much—they’re just small pipes that stick up through the roof—but they play a big role in keeping sewer gases out. These vents help your system “breathe” by balancing air pressure in your drain lines. That balance prevents odors from rising through your sinks, tubs, or floor drains.
Leaves, bird nests, or ice during Texas cold snaps can clog those vents and stop them from working. That blockage creates a vacuum effect in your pipes, which can suck the water out of your traps. And without that protective barrier, septic smells have a clear path inside your house.
Full septic tank
A full septic tank is a common cause of sewer odors in your home. Solid waste builds up in your septic tank, so schedule a pump-out every 3 to 5 years based on your household size.
If you don’t pump your septic tank regularly, solid waste can block the openings where wastewater flows in and out. That can lead to backups, slow drains, or even system failure. As that pressure builds, it can push foul-smelling gases up through your plumbing and into your home. A full tank also speeds up waste breakdown, which creates even more foul-smelling gas.
Need septic tank pumping? Call Bacon Plumbing at now to schedule fast, reliable service.
Clogged drain field (Biomat Build)
Your septic system sends treated water into the ground through a part of the yard called the drain field, or leach field. Pipes with small holes spread the water into gravel, and over time, a slimy layer called a biomat forms around them. This layer plays a helpful role by filtering out remaining contaminants.
But when the biomat grows too thick, usually because of system overuse or age, it can block the flow of wastewater. This pushes wastewater and sewer gases back toward your home. As the system struggles to drain, it loses oxygen, which leads to even stronger and more unpleasant odors.
Heavy rainfall
After a heavy downpour or days of steady rain, you might notice a septic smell in the house. That’s because heavy rainfall can flood the soil around your drain field. When the ground becomes saturated, it can’t absorb any more water—including the treated wastewater from your septic system.
Instead of draining away like it should, that water backs up. The system stalls, and sewer gases that would normally stay underground can creep back through your plumbing and into your home. These smells tend to show up during or right after storms and can stick around until the soil dries out.
Cracked or damaged pipes
The pipes that connect your home to your septic tank run underground and are exposed to a lot over time. Tree roots, shifting soil, freezing and thawing, or just plain aging can all cause these pipes to crack or break down.
When that happens, sewer gases can escape into the surrounding soil. Those gases can then sneak into your home through cracks, utility gaps, or basement walls. This is a common issue in older homes, particularly those with cast iron or clay pipes that are well past their expected lifespan.
How Bacon Plumbing Heating Air Electric Can Help
If your home smells like sewage, there’s a good chance your septic system is behind it—and waiting too long can make things worse. At Bacon Plumbing Heating Air Electric, we specialize in finding and fixing the exact cause of septic-related odors in your home.
Our licensed technicians serve the entire Dallas-Fort Worth area, and we’re trained to handle every part of your septic system—from P-traps and vent stacks to the tank, pipes, and drain field. Whether it’s a dry trap letting in gas or a full tank forcing odors back into your home, we’ll get to the root of the issue fast.
Need expert septic help now? Call Bacon Plumbing Heating Air Electric today at . We’re available 24/7.
