A sewer backup means wastewater can't leave your home through the main sewer line, so it comes up through the lowest drains, usually a basement floor drain, shower or toilet. Stop using all water right away, keep people and pets away from the sewage, and call a plumber. Common causes are clogs, tree roots and a damaged or sagging sewer pipe.
Reviewed by Ron Olsen, Master Plumber, certified in Washington
What Causes Sewer Backups
- Main line clog
- Grease, wipes and other items build up and block the main sewer line.
- Tree roots
- Roots grow into joints and cracks, especially in older clay and cast iron pipe.
- Damaged or sagging pipe
- Cracks, collapses or a sag (belly) in the line collect waste and cause blockages.
- Municipal sewer overload
- Heavy rain can overload the city sewer and push water back into homes.
What to Do Right Now
- Stop using water anywhere in the house. Don't flush, shower or run appliances.
- Keep children and pets away from the affected area.
- Wear gloves and boots if you must go near the sewage.
- Don't use chemical drain cleaners.
- Photograph the damage for your insurance claim.
When to Call a Plumber
Call a plumber for any sewer backup. The line needs to be cleared with professional equipment and usually inspected with a camera to find the cause. Sewage cleanup may also need a water damage remediation company.
The repair is usually part of sewer line repair, which explains what the plumber does and what affects the cost.
Sewer Backups by City
What our city pages say about sewer backups:
- Pottstown, PA: Old terra cotta laterals crack and fill with roots.
- Antioch, CA: Clay laterals near the older downtown crack and take in roots.
- Elmhurst, IL: In heavy storms, sewer water can rise through floor drains and fixtures.
- Pawtucket, RI: Old laterals crack and back up, worst in heavy rain.
- Warner Robins, GA: Roots and age block the laterals of 1950s and 1960s houses.
- Livonia, MI: Roots, grease or heavy rain send water up through the floor drain.
- Lynn, MA: Old laterals and combined sewers back up in heavy rain.
- Norwalk, CT: Roots and cracks in old laterals send sewage back to the basement.
Sewer Backup Questions
Is sewage backup dangerous?
Yes. Sewage contains bacteria and other pathogens. Avoid contact, keep the area ventilated, and have contaminated materials cleaned or removed properly.
How can I prevent another backup?
Keep wipes and grease out of drains, have the line inspected with a camera, and ask a plumber about a backwater valve if your area floods.