You’re hearing gurgling from the sink when the washing machine drains, and it’s worrying — this usually means the pipework is struggling to breathe or clear water properly.
The sink bubbles or gurgles loudly every time the washing machine pumps out water.
Is this your problem?
What to do
- This usually means air is being pulled through the sink trap because water can’t flow away fast enough.
- First, check the sink isn’t slow to drain. If it is, that’s your starting point.
- Pour a full kettle of hot (not boiling) water down the sink to loosen grease.
- Then use a plunger: block the overflow with a damp cloth and plunge firmly for 20–30 seconds.
- Run the washing machine again and listen. If the noise reduces, the blockage was partial.
The washing machine drain hose connects under the sink, and the gurgling is new.
Is this your problem?
What to do
- Look under the sink at the spigot connection where the washer hose joins.
- If it’s blocked with detergent sludge, remove the hose and clean the spigot thoroughly.
- Refit the hose securely and make sure it loops upward before dropping into the waste.
- This loop stops dirty water and air being sucked back.
The sink drains fine, but the gurgling is loud and sudden when the machine empties.
Is this your problem?
What to do
- This points to a poor vent or air lock in the waste pipe.
- UK homes often rely on air admittance valves or shared stacks.
- Check if there’s a small grey or black valve under the sink — if stuck, it can’t admit air.
- Lightly tap it and make sure it’s upright and not clogged.
The gurgling comes with bad smells or water rising in the sink.
Is this your problem?
What to do
- Stop using the washing machine for now.
- This suggests a deeper blockage in the branch or main waste pipe.
- Repeated plunging won’t fix this and may force dirty water back.
- This is the point to call a plumber with proper rodding or jetting gear.
Is it safe to fix this yourself in the UK?
Safe DIY
- Plunging the sink correctly.
- Cleaning the washing machine spigot.
- Checking and reseating the trap and hose.
Do NOT do
- Use caustic drain cleaners — they damage pipes and seals.
- Remove shared waste pipes in flats.
- Force tools deep into the pipework.
When to stop
- If smells persist.
- If water backs up.
- If gurgling happens at multiple fixtures.
When to call a plumber
- Repeated gurgling despite clear traps.
- Any overflow risk.
- Flats or shared drainage systems.