By Double J Liner Repair · Troubleshooting · Published 2026-10-23
A sewer smell inside the house is unpleasant and unsettling. The good news is that many causes are simple. The bad news is that some point to a cracked or failing sewer line that needs attention.
Here is how to work through the possibilities, starting with the easiest.
Every drain has a curved trap that holds water to block sewer gas. If a fixture is rarely used, like a guest bath shower or a floor drain, that water can evaporate. Run water in every drain for a minute and see if the smell fades.
The wax ring under a toilet seals it to the drain. If the toilet rocks or the seal has failed, sewer gas can escape around the base. A plumber can reset the toilet with a new seal.
Plumbing vents let sewer gas exit through the roof. A blocked or damaged vent can cause gurgling drains and odors indoors. Bird nests, debris, or a disconnected vent pipe are common culprits.
If the simple fixes do not solve it, the cause may be a crack in the drain line under the slab or in the main sewer line. Corroded cast iron and root-damaged clay pipe are common sources. Odor that is strongest near floors, along a wall, or outside near the cleanout points in this direction.
A camera inspection can locate the crack precisely.
If the camera finds a cracked line, UV-cured lining can seal it from the inside without breaking up the slab or digging up the yard. The new liner is seamless, so sewer gas and wastewater stay inside the pipe where they belong.
Sewer gas can contain gases that are unpleasant and potentially harmful at higher concentrations. Persistent odors should be investigated promptly.
Intermittent odors can come from traps that dry out, vent issues that appear in certain weather, or a cracked line that leaks more when drains are used heavily.
Often, yes. UV-cured lining works through existing access points.
Double J Liner Repair offers sewer camera inspections and free estimates on no-dig sewer repair in San Antonio, backed by a 10-year warranty. Learn more about sewer repair or read more sewer and pipe repair guides.
Double J Liner Repair · 1800 NE Interstate 410 Loop #216, San Antonio, TX 78217 · Phone: (210) 802-2018 · Email: Info@doublejlinerrepair.com
Hours: Monday–Friday 8:00 AM–6:00 PM, Saturday 9:00 AM–2:00 PM, Sunday closed.