Symptoms
- Nearby drain bubbles or gurgles during the washer's drain cycle
- Water may rise slightly in the other drain
- Washing machine itself drains fine on its own
- Problem is worse with larger loads
Likely causes
- CommonPartial clog in the shared branch drain lineThe washer discharges a large volume quickly, and a partial blockage downstream forces air (and sometimes water) back up the path of least resistance.
- PossibleUndersized or clogged standpipe or drain line for the washerLint and debris can build up in the washer's own drain line over time.
- PossibleVent issue affecting the shared lineSimilar to general gurgling causes, a vent problem can worsen this symptom.
- Less commonClog further down the main lineWorth considering if other symptoms of a bigger backup are present.
What to do
- Check the nearby sink or floor drain for a local clog first and clear it with a plunger or hand snake.
- Clean the washing machine's own lint filter or drain hose connection if accessible, since a partially clogged hose can affect flow speed.
- Run the washer's drain or spin cycle alone and watch the other drain closely to confirm the timing of the bubbling.
- If bubbling continues after clearing the local drain, the clog is likely in the shared line between the two fixtures.
- Consider snaking the shared drain line from the nearest accessible cleanout if you're comfortable doing so.
- If bubbling is significant or water actually backs up rather than just bubbling, treat it more seriously and call a plumber.
Tools and parts
- Plunger
- Hand-crank drain snake
When to call a pro
Call a plumber if bubbling is accompanied by actual backup or doesn't improve after clearing the nearby drain.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.