Sewer Smell in Your Arlington House? 6 Causes and How to Fix Them

A sewer smell inside the house usually comes from one of six sources: a dry P-trap in a drain that is rarely used, a toilet with a failed wax ring, a blocked or cracked plumbing vent, a loose cleanout cap, a dishwasher or washer drain problem, or a broken drain pipe under the slab. The first four are easy to check. A smell that stays after those checks often means a sewer leak under the floor. Call (817) 285-5426.

Our leak detection Arlington TX team finds sewer leaks with cameras and smoke or pressure tests, without breaking the floor first.

What are the 6 most common causes?

1. A dry P-trap

Every drain has a U-shaped trap that holds water and blocks sewer gas. In a guest bath, a basement-style floor drain or a laundry sink, that water evaporates in a few weeks. Run water in every drain for 30 seconds and see if the smell fades.

2. A loose toilet or failed wax ring

If the smell is strongest near a toilet, the wax ring may have failed. A toilet that rocks breaks the seal. You may also see water at the base.

3. A blocked or cracked vent

Vent pipes on the roof let sewer gas out above the house. A bird nest, leaves or a crack in an attic vent pipe can push gas back inside. Gurgling drains are a clue.

4. A loose cleanout cap

Cleanouts in a closet, garage or outside wall can lose their cap or seal. Tighten it and check the threads.

5. An appliance drain

Washers and dishwashers need an air gap or a high loop. Without one, sewer air can come back through the hose. A dirty dishwasher filter can smell like sewage too.

6. A broken drain pipe under the slab

Arlington's expansive clay soil moves the slab, and older cast iron drains crack and corrode. Sewer gas then rises through slab cracks, around plumbing penetrations or under baseboards. This is the cause to rule out when the smell will not go away.

Is sewer gas dangerous?

Small amounts of sewer gas mostly cause odor, headaches and nausea. Higher levels in a closed room can be harmful, and methane in sewer gas can burn. If the smell is strong, open windows, avoid flames and call for help. A smell like rotten eggs near a gas appliance may be natural gas, not sewer gas. Leave the home and call Atmos Energy or 911 from outside. Our gas leak warning signs guide explains the difference.

How do pros find a sewer leak under the slab?

A tech starts with a camera inspection down the main cleanout to look for cracks, root intrusion, offsets or a belly in the line. A hydrostatic test plugs the line and fills it with water to see if it holds. A smoke test pushes harmless smoke into the drains to show where gas escapes. Sewer camera work in Arlington runs about $150 to $400.

Read our sewer camera inspection guide and our sewer hydrostatic test guide to see what each test shows. For the next step after a leak is found, see sewer leaks under the slab.

General estimates for Arlington, TX in 2026. Your exact price is confirmed before any work begins.

What can you do today?

• Run water in every sink, tub, shower and floor drain.
• Check each toilet for rocking or water at the base.
• Look for cracked grout or gaps around the tub drain.
• Note when the smell is worst, such as after a flush, after rain or on hot days.
• If it stays, call a leak detection company to test the drain lines.