A sewage smell in house plumbing isn’t just a nuisance—it’s a sign that something might be wrong behind the scenes. At True Blue Plumbing, we work with homeowners in Snellville, GA every week to find and fix the causes of foul odors in their homes. While the smell alone might seem harmless, it often points to issues that can grow worse if ignored. Let’s explore the most common reasons behind sewer odors and what you can do to stop them.
Dry Drain Traps Can Cause Sewage Smell in House
One of the most frequent causes of a sewage smell in house plumbing is something simple: a dry drain trap. The P-trap is a curved pipe under sinks, tubs, and floor drains that holds water. This water forms a seal that blocks sewer gases from coming up into your home.
When a drain goes unused for long periods—like in a guest bathroom or basement—the water inside the trap can evaporate. Once it dries up, nothing stops sewer gases from rising through the pipe. You may notice the smell near unused sinks or laundry rooms. To fix this, simply run water down the drain for 10 to 15 seconds every few weeks to keep the trap full.
Sewer Line Damage or Blockages
A more serious reason for a sewage smell in house is damage to the main sewer line. This pipe connects your home’s plumbing to the municipal sewer or septic tank. If it cracks or becomes clogged, waste can leak into your yard, foundation, or even back into your drains.
Common causes include tree root intrusion, old cast iron or clay pipes, shifting soil, or buildup from grease and debris. You may hear gurgling sounds or notice water backing up in low drains. If the smell gets stronger when multiple fixtures are used at once, the main line could be blocked.
At True Blue Plumbing, we use advanced video inspection tools to quickly diagnose the problem and recommend repairs—before damage spreads or health risks increase.
Plumbing Vent Issues and Sewage Smell in House
Your plumbing system includes a network of vent pipes that balance pressure and release gases outside. These vents usually run through your roof. When they’re clogged or improperly installed, sewer gases can’t escape. Instead, they get pushed back into your home.
Bird nests, leaves, and other debris can block these vents. In some cases, vent pipes may have been incorrectly placed during a remodel or original construction. Symptoms include a sewage smell in house, slow drains, and bubbling toilets. Vent issues often go unnoticed until they cause visible signs of trouble.
A professional plumber can inspect your vent system and ensure it’s working properly. If repairs or modifications are needed, we’ll guide you through the options.
Septic Tank Backups Can Trigger Sewage Smell in House
Homes that use septic systems face a different set of challenges. If the tank gets full or the drain field fails, wastewater may flow back into your plumbing. That can lead to a sewage smell in house, especially in bathrooms and kitchens.
Septic systems require regular pumping, usually every 3 to 5 years. Neglecting this maintenance increases the risk of backups, odors, and even system failure. Signs include slow flushing, standing water in the yard near the drain field, and foul smells indoors.
If you’re not sure when your tank was last pumped, it’s time to schedule service. True Blue Plumbing provides septic system inspections and can connect you with trusted local pumping services.
Bacterial Buildup in Dirty Drains
Not all sewage smells are caused by actual sewage. Sometimes, the problem lies inside the drain itself. Bacteria feed on organic material like food, hair, and soap scum. As they grow, they release foul-smelling gases that mimic sewer odors.
This often happens in kitchen sinks and bathroom showers. Even if water drains normally, the buildup on the pipe walls can cause a smell to linger. Start by flushing the drain with hot water, baking soda, and vinegar. If that doesn’t work, try an enzymatic drain cleaner.
For long-term relief, True Blue Plumbing offers drain cleaning services, including hydro jetting. This method uses high-pressure water to remove years of grime and eliminate odors at the source.
Toilet Wax Ring Leaks and Odors
Toilets rely on a wax ring to create a seal between the base and the floor drain. If the wax dries out, cracks, or becomes misaligned, sewer gases can escape every time you flush. This is a common cause of sewage smell in house bathrooms.
You might notice the toilet shifting slightly when you sit, or see water pooling around the base. These are signs that the seal is broken. Replacing a wax ring isn’t complicated, but the toilet must be removed to do it. Many homeowners prefer to leave this job to a professional to ensure a tight, odor-free fit.
Mold and Mildew Can Smell Like Sewage
In some cases, the odor isn’t from your plumbing at all. Mold and mildew produce strong, musty smells that homeowners often confuse with sewer gas. These odors usually come from hidden water leaks behind walls, under sinks, or near appliances.
Mold thrives in damp, dark places, so early detection is key. Look for discoloration on walls, warped baseboards, or peeling paint. If you suspect mold, fix any leaks immediately and improve ventilation in the affected area. If the smell remains, consider having your home inspected for hidden mold growth.
When to Call a Plumber for Sewage Smell in House
If you’ve tried flushing drains, refilling traps, and cleaning fixtures, but the sewage smell in house persists, it’s time to call in a professional. Sewer gases can contain harmful compounds like hydrogen sulfide and methane, which may cause health issues with prolonged exposure.
Persistent odors also suggest a deeper issue—one that won’t go away on its own. Whether it’s a venting problem, a sewer line crack, or a failing septic system, early intervention prevents more costly repairs later. At True Blue Plumbing, we provide fast, accurate diagnosis and repair throughout Snellville, GA.
Don’t Ignore That Sewage Smell in House Plumbing
The longer a sewage smell in house goes unchecked, the worse it can get. Beyond the odor, there’s often a real issue with your plumbing system that needs attention. From simple fixes like running water in unused drains to major repairs like replacing sewer lines, every problem has a solution.
Don’t wait for the problem to escalate—call True Blue Plumbing today for a fast, honest inspection. Our licensed plumbers proudly serve Snellville, GA and surrounding areas with dependable service and upfront pricing. Contact us now to schedule your appointment and get your home smelling fresh again.
