Quick Answer:
If you find a new wet spot after a scheduled sewer cleaning, stop using water, dry and mark the wet area, then flush fixtures one at a time to see which drain pressurizes the leak. Inspect the cleanout cap and gasket, check nearby joints and coupling bands for dampness or grease streaks, and—if it’s safe and accessible—expose the cleanout coupling to look for cracked fittings or torn seals before covering up. Call a professional if you see wastewater, the leak gets worse when other fixtures run, or excavation looks necessary.
Why This Happens
Sewer cleaning puts water and pressure through the line to clear blockages. That pressure can reveal weak points that were holding just enough to stay dry: old gaskets, shifted couplings, cracked fittings, or corroded joints. A failing cleanout cap or a torn gasket can weep under pressure. In more severe cases the cleaning can dislodge debris or open a crack and lead to a sudden wet spot or even a small Basement floods after cleaning.
Step-by-Step What to Do
1. Stop water use, dry and mark the wet area
Turn off faucets and appliances that use water. Use towels to soak up the area and put a visible mark (tape, chalk) where it was wet so you can see if it spreads or starts again. This makes it easier to track whether a single drain or multiple fixtures pressurize the leak.
2. Flush fixtures one at a time
With the area marked, flush or run one fixture at a time (toilet, tub/shower, laundry sink). Watch the marked spot as each fixture runs. If the wet spot appears or grows only when a specific fixture runs, that points to a particular branch or trap pressurizing the leaking joint.
3. Inspect the cleanout cap and gasket
Open the area around the cleanout (remove the access cover if you have one) and inspect the cleanout cap and its gasket. Look for missing, cracked, compressed, or shifted seals. Caps can loosen during cleaning or seals can fail, allowing water to escape under pressure.
4. Check nearby joints and coupling bands
Run your hand (gloved) along accessible joints, coupling bands, and cast-iron clamps. Look for dampness, fresh grease streaks, or small drips. Grease or dark streaks often show where wastewater has tracked down a joint even if it’s not actively dripping.
5. Expose the cleanout coupling if accessible
If the cleanout coupling is aboveground or lightly buried and it’s safe to do so, carefully dig around it enough to inspect the fitting and seal faces. Look for cracked fittings, torn seals, or deteriorated pipes. Don’t bury it again until you’re satisfied the leak source is addressed or a repair plan is in place.
6. Document and contain
Take photos, note which fixtures caused a reaction, and put down a drip pan or rags to protect the floor. If you find raw sewage, stop and call a professional (see below).
What Not to Do
- Avoid over-tightening cast-iron band clamps — that can crack the pipe or the fitting and often makes the damage worse.
- Do not rely on wrapping temporary tape or materials as a permanent fix. Tape can hide a failing joint and will fail again when pressure returns.
- Don’t ignore sewer water. If wastewater is present, the leak gets worse when other fixtures run, or excavation seems necessary, call a pro; a trained technician can diagnose cracked pipe or bad seals safely.
When to Call a Professional
Call a licensed plumber when any of the following are true:
- There is visible wastewater or sewage in your basement or around the cleanout.
- The wet spot grows when other fixtures run or you can’t isolate which drain is causing it.
- There is a visible crack in a fitting or you need to excavate to access the cleanout coupling.
- You’re unsure what caused the leak or you can’t stop it with basic containment steps.
A professional has the tools to pressure-test the line, inspect with a camera, and make repairs to cracked pipe or replace bad seals safely.
Safety Notes
- Wear gloves and eye protection. Avoid direct contact with wastewater; it can carry bacteria and pathogens.
- Don’t use electrical appliances near standing wastewater. Turn off breakers if water is near outlets and call an electrician if you suspect electrical risk.
- Ventilate the area if you smell sewer gas and avoid open flames — sewer gas can include combustible gases in rare situations.
- If you find sewage, limit exposure and call a professional for cleanup and repairs.
Common Homeowner Questions
- Why did the leak start only after cleaning? The cleaning raised pressure and exposed weak seals or hidden cracks that were previously holding only under normal flow.
- Can I patch a leaking coupling myself? Small weeps from an accessible gasket might be temporarily contained, but permanent repairs—especially with sewage—are best done by a pro.
- What if I see Standing water after cleaning? Stop water use, document the area, follow the step-by-step checks, and call a professional if the water is sewage or the leak continues when other fixtures run.
More in this topic
For more related fixes and similar symptoms, see Post-Snaking Main Line Problems.