Symptoms
- Water spills out around the drain hose during the wash cycle
- Water backs up onto the laundry room floor
- Standpipe area may smell musty
- Overflow happens consistently during the same part of the cycle
Likely causes
- CommonLint and detergent buildup clogging the standpipeWashing machines discharge a lot of water quickly, and any narrowing from buildup can't keep up.
- PossibleDrain hose inserted too far into the standpipeCan create a seal that causes back-siphoning or reduced airflow, worsening overflow.
- PossibleStandpipe too short or improperly ventedAn improperly installed standpipe can struggle with a modern high-efficiency washer's discharge rate.
- PossibleClog further down the shared laundry drain lineA blockage past the standpipe backs water up out of it.
What to do
- Pause or stop the washing machine if it's actively overflowing to prevent further water damage.
- Check that the drain hose isn't inserted too deep into the standpipe; it should hook in loosely, generally no more than a few inches, with an air gap around it.
- Clean any visible lint or debris from the top of the standpipe opening.
- Run a smaller test load and watch the standpipe closely during the drain cycle to see how much water backs up.
- If it still overflows, use a hand-crank drain snake down the standpipe to check for a clog.
- If the standpipe is short, improperly vented, or simply undersized, that's a plumbing modification best handled by a professional.
- Once cleared, run a normal load and confirm the standpipe handles the discharge without overflowing.
Tools and parts
- Hand-crank drain snake
When to call a pro
Call a plumber if the standpipe is undersized, poorly vented, or a snake doesn't clear the overflow, since it may need a plumbing modification.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.