A sewer smell in your house is most often caused by a dry P trap, a bad toilet wax ring, a blocked plumbing vent, a clogged drain, or a cracked sewer line. The rotten egg smell comes from hydrogen sulfide in sewer gas. Start by running water in every drain you rarely use. If the odor continues, call a plumber to find the leak.
⚡ QUICK SUMMARY
Sewer gas smells like rotten eggs because of hydrogen sulfide. The top causes are dry P traps, loose toilet seals, blocked vents, and cracked pipes. Easy fix: run water in unused drains. Hard fix: a camera inspection finds cracks in the sewer line. Sewer line repair in Stockton runs about $2,000 to $5,000. JC Sewer & Drain Plumbing finds and fixes sewer odors across Stockton and San Joaquin County. Call (209) 403-9023.
You come home to your house near the University of the Pacific after a week away. You open the door. It smells like rotten eggs. Nothing is spoiled in the fridge. The smell is strongest in the guest bathroom. That is sewer gas, and it is telling you something.
JC Sewer & Drain Plumbing is a family owned and operated plumbing company in Stockton, California. We have served San Joaquin County since 2011 under California State Plumbing License #845004. We do drain cleaning, sewer line repair, and video camera inspection and locating. This guide explains what causes a sewer smell in the house, if it is harmful, and how to get rid of it.
Rotten egg smell that will not go away? Call and we will find the source.
Call (209) 403-9023What Does Sewer Gas Smell Like?
Sewer gas smells like rotten eggs. That smell comes from hydrogen sulfide. Sewer gas is a mix of gases that forms when waste and organic matter break down. It also contains methane and carbon dioxide, per the Wisconsin Department of Health Services. Your plumbing system is built to keep this gas in the sewer lines and send it out through vent pipes on the roof. A sewer gas smell inside means that seal has failed somewhere.
Is Sewer Gas Harmful?
Small amounts of sewer gas are mostly unpleasant, but they are a warning sign. The Wisconsin health department says low levels of hydrogen sulfide can cause eye and breathing irritation, headaches, and nausea. Prolonged exposure or high concentrations are more serious. Methane can also burn. Do not ignore the smell.
⚠️ Safety First
If the sewer smell is very strong, or people in the home feel sick, dizzy, or have headaches, open windows, leave the house, and call for help. Do not light a flame near a strong sewer gas odor.
What Causes Sewer Smell in a House?
1. A dry P trap
Every sink, tub, and floor drain has a P trap. The curved section of pipe holds water. That water seal blocks sewer gas. If a drain goes unused, the water dries up. The Illinois Department of Public Health notes that sewer drains with dry traps can let hydrogen sulfide gas into the home. This is the most common cause.
2. A bad toilet wax ring
A wax ring seals the toilet to the drain pipe in the floor. If the toilet rocks or the ring breaks, sewer gas leaks out around the base. You may also see water on the floor.
3. Blocked plumbing vents
Plumbing vents on the roof let sewer gas escape and keep air pressure right in the drain lines. Leaves, nests, or debris can block a vent stack. Then gas pushes back into the house. Gurgling drains are a telltale sign.
4. Clogged or slow drains
Hair, grease, and organic matter build up in drain pipes and rot. That creates a foul odor right at the sink. Slow drains and odors often go together.
5. Cracked pipe or leaky pipes
A cracked pipe in a wall, under a floor, or in the main sewer line lets sewer gas out. Tree roots can crack a sewer line. Heavy rain can make the smell worse.
6. A loose cleanout cap
The sewer cleanout gives plumbers access to the line. If the cap is loose or missing, gas escapes.
7. Washing machine drain problems
A washer standpipe with no trap, or a bad trap, can let sewer smell into the laundry room.
How Do You Get Rid of Sewer Gas Smell?
Run water in every drain
Run water for a minute in every sink, tub, shower, and floor drain. This refills dry P traps. Many sewer odor problems stop right here.
Check the toilets
Rock each toilet gently. If it moves, or the smell is at the base, the wax ring likely needs replacing.
Clean the drains
Use baking soda and vinegar, then hot water, to clear buildup. Skip harsh chemicals.
Check the cleanout cap
Make sure the sewer cleanout cap outside is tight.
Call a plumber
If the odor continues, a plumber can smoke test the lines and run a camera to find the leak.
💡 Pro Tip
For a guest bath or floor drain you rarely use, pour in water once a month. A spoon of mineral oil on top slows evaporation in hot Stockton summers. That keeps the water seal in place.
How Do Plumbers Find Sewer Gas Leaks?
Professional plumbers find sewer gas leaks with a few tools. A smoke test pushes harmless smoke into the sewer system and shows where it escapes. A video camera inspection shows cracks, roots, and breaks inside the sewer line. We also check vent pipes, traps, and seals. Then we give you the appropriate repair, not a guess.
How Much Does It Cost to Fix a Sewer Smell?
Many fixes are cheap. Refilling a P trap is free. A new wax ring or P trap is a small repair. A plumbing vent stack repair costs $300 to $1,200 for a small crack, per HomeAdvisor 2025. A cracked sewer line is bigger. In Stockton, sewer line repair costs about $2,000 to $5,000, and trenchless repair runs $4,000 to $10,000, per local cost data. Stockton requires a plumbing permit for sewer line work under the City of Stockton Municipal Code.
Sources: HomeAdvisor 2025 plumbing stack guide; Stockton plumbing cost data, 2025. Financing available.
Sewer Smell Questions
Why does the sewer smell come and go?
A trap that dries out slowly, wind across a roof vent, or heavy rain can make the smell come and go. It still means something needs fixing.
Is it safe to sleep in a house with sewer gas?
A faint smell from a dry trap is usually not an emergency. Refill the trap and air out the room. If the smell is strong or people feel sick, leave and call for help.
Why do I smell sewer when no one else does?
People notice smells differently. Trust your nose. Check the traps in rooms you rarely use.
Can a sewer smell mean a broken sewer line?
Yes. A smell with slow drains, gurgling sounds, or wet spots in the yard can mean a cracked line. Read our list of signs you need sewer line repair.
The Bottom Line
A sewer smell in your house is a warning sign, not just a bad odor. Start with the easy fix: run water in every drain. Check the toilets and the cleanout cap. If the odor continues, call a plumber to find the cracked pipe or blocked vent. We Clean Out Your Pipes Not Your Pocketbook, and we get it right the first time.
About the Author
JC Sewer & Drain Plumbing Inc
Family owned and operated Stockton plumbing company, serving San Joaquin County since 2011. California State Licensed Plumber, License #845004. Voted #1 Best Stockton Plumbing Company in the Best of Stockton awards, and KSTN called us "The Super Heroes of Plumbing."
Stop the Sewer Smell for Good
JC Sewer & Drain Plumbing offers drain cleaning, camera inspections, and sewer repair across Stockton and San Joaquin County. Written quotes and financing available. Or contact us online.
Call (209) 403-9023Open seven days a week. Serving Stockton, Lodi, Manteca, Lathrop, Tracy, Ripon, Escalon, and French Camp.
