Sewage backs up into a basement because the basement floor drain is usually the lowest opening in the plumbing system. When the main sewer line is clogged, damaged, or overwhelmed, wastewater has nowhere to go and rises through that lowest point first. Common causes include grease and wipes, tree roots, broken pipes, and heavy rain that overloads city sewers.
A Clog in the Main Line
Everything that leaves your home flows through one main line. Grease, wipes, paper towels, and other items can build up there over time. Once the line is blocked, water from upstairs fixtures backs up into the basement drain.
Roots and Pipe Damage
Older sewer pipes made of clay or cast iron can crack or separate at the joints. Tree roots grow toward the moisture and slip inside, where they trap waste. Pipes can also sag, creating low spots where solids collect. A camera inspection can show which of these is happening.
Heavy Rain and City Sewers
During intense storms, city sewers can fill faster than they drain. Water may then flow back toward homes connected to the system. Some homes use a backwater valve, which is a one-way valve that helps stop sewage from flowing back in. A plumber can tell you whether one makes sense for your home.
What to Do When It Happens
- Stop using all water in the home
- Keep everyone out of the basement
- Do not touch the water without gloves and boots
- Stay away from outlets or appliances near the water
- Take photos for insurance before cleaning
Clean only after the line has been cleared, and use disinfectant on all surfaces the water touched.
A camera inspection and line clearing is the best way to find the real cause. Some homeowners also use the visit to plan longer-term sewer line upgrades. Call JPR Plumbing at (833) 603-1840.