How do I unclog a floor drain?
By the Drain Guru team · Updated September 27, 2026
Quick answer
Lift the grate, scoop out debris, and flush with a bucket of water. For a local clog, use a drain snake or an air-pressure opener with a wide cone head. If water or sewage comes UP out of a basement floor drain, especially when other fixtures run, that's a main sewer line blockage and needs a plumber.
Local clog vs. sewer backup
- Slow to drain water you pour in: a local clog near the drain. You can usually clear it.
- Water comes up out of it when the washer drains or a toilet flushes: the main line is blocked downstream. Stop using water and call a plumber.
Clearing a local clog
- Remove the grate (it may be screwed down) and clear out lint, sand or debris by hand.
- Pour a bucket of water in to see how it drains.
- Push through the clog with a drain snake, or seal an air-pressure opener's cone head over the opening and fire.
- Flush with another bucket of water.
A floor drain that smells like sewer gas usually has a dry trap. Pour a gallon of water in every month or two to refill the seal.
More questions
Why does my basement floor drain back up when I do laundry?
The washer dumps a lot of water fast. If the main line is partly blocked, that water has nowhere to go and rises at the lowest opening: the floor drain.
Related answers
General information only. Plumbing codes, prices and landlord-tenant laws vary by location. For gas, electrical, sewer-line or structural problems, contact a licensed professional.