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Garage and basement floor drain backups
In homes where the garage or basement is the lowest floor, a floor drain or ground-floor fixture is often the first place sewage appears when the main line is blocked. Water takes the lowest exit.
If it's backing up now
- Stop using water everywhere in the building.
- Keep people and pets away from the water.
- Call a drain professional to clear the main line, and follow the backup steps.
Backwater valves
A backwater (backflow) valve lets wastewater leave the building but closes if sewage tries to flow back in from the street. They're relevant where fixtures sit below the level of the next upstream manhole or the street. Plumbing codes and local rules set when one is required. Ask a licensed plumber whether your property needs one and about permitting.
Prevent repeat backups
- Camera-inspect the line to find roots, bellies, or breaks.
- Keep grease and wipes out of drains (see prevention).
- Make sure the floor drain's trap has water in it (pour some in occasionally) to keep sewer gas out.