A sewage backup usually shows up at the lowest drain in the house: the basement floor drain, a basement shower, or the lowest toilet. It can be a slow seep or several inches of water in minutes. Either way, the water carries bacteria and other contaminants, and anything porous it touched (carpet, pad, drywall, insulation) is usually removed rather than cleaned.
Common causes
- Tree roots growing into an older clay or cast-iron sewer lateral
- Grease, wipes (even ones labeled “flushable”), and other debris clogging the line
- A sagging or broken section of the line between the house and the city main
- Heavy storm water getting into the sewer system and overloading it
- A failed sewage ejector pump in a basement bathroom
What to do right now
- Stop running water: no flushing, laundry, dishwasher, or showers until the line is cleared.
- Keep children, pets, and anyone with health concerns away from the area.
- Do not touch the water without gloves and boots. Wash thoroughly if you do.
- Turn off power to the area if you can do it without stepping in water.
- Call a plumber or sewer service to clear the line, and call {{PHONE}} for a referral to a cleanup provider.
What professional sewage cleanup involves
Providers typically wear protective gear, extract the contaminated water, remove affected porous materials, clean and disinfect hard surfaces, and then dry the area. Some also run air scrubbers to deal with odor. Because the water is contaminated, the industry generally treats it as the highest risk category, which changes what can be saved.
Whose line is it?
In general, the homeowner is responsible for the sewer lateral that runs from the house to the public main, and the local sanitation district handles the main itself. If you think the backup came from the main, call the sanitation or water district listed on your utility bill. A camera inspection by a plumber can show where the blockage is.
Prevent the next one
- Ask a plumber about a backwater valve on the main line.
- Keep grease and wipes out of drains.
- Have older lines scoped if you have repeated slow drains or gurgling.
- Check your insurance for a sewer or drain backup endorsement; many basic policies exclude it.
Related: flooded basement cleanup and mold remediation.
Quick answers
Can I clean up a small sewage backup myself?
A very small amount on a hard, non-porous floor is sometimes handled by homeowners with gloves and disinfectant. Anything on carpet, drywall, or larger areas should be handled by a professional.
Will the smell go away on its own?
Not usually, if contaminated materials are left in place. Removing affected materials and drying the area is what removes the source of the odor.