Short answer: Turn off the disposal’s power first: unplug it and switch off the breaker. Then find where the water comes from. Bob Vila explains that a leak at the top is usually the sink flange (old plumber’s putty or loose mounting bolts), a leak at the side is the dishwasher hose clamp or the drain pipe gasket, and a leak from the bottom, often near the reset button, means an internal seal has failed or the housing cracked, so the unit usually needs replacing.
Quick diagnosis
| What you notice | Most likely cause | What to check | Call a pro? |
|---|---|---|---|
| Water around the top, under the sink flange | Failed putty or loose mounting | Fill the sink with water and watch | If you cannot reseal |
| Drip at the dishwasher hose connection | Loose clamp | Tighten the clamp | Rarely |
| Drip at the drain pipe connection | Worn gasket or loose discharge bolts | Check the gasket | Rarely |
| Water from the bottom or reset button | Internal seal failure or cracked housing | Turn off power | Replace the unit |
| Water from somewhere else under the sink | Faucet, sprayer, P-trap or dishwasher hose | Lay newspaper and trace drips | Sometimes |
Make it safe and find the leak
- Unplug the disposal and turn off its breaker.
- Put dry newspaper or paper towels under the unit.
- InSinkErator suggests plugging the sink, filling it with water and watching for drips; then pulling the plug and running water to test the drain connections.
- Check the faucet, sprayer, P-trap and dishwasher hose too, since water can run down and look like a disposal leak.
Fixes by location
- Top: remove the unit, reseal the sink flange with fresh plumber’s putty and retighten the mounting assembly.
- Dishwasher inlet: tighten or replace the hose clamp.
- Drain connection: replace the gasket and tighten the discharge bolts.
- Bottom: replace the disposal; on older units other seals tend to fail too.
When to call a professional
- Water comes from the bottom of the unit.
- The disposal also hums, trips the breaker or smells burnt.
- You are not comfortable disconnecting the unit and the plumbing.
What it usually costs
Bob Vila reports professional disposal replacement at about $400 on average, parts and labor included; installing it yourself saves about $90 to $200 in labor.
Frequently asked questions
Why is my garbage disposal leaking from the bottom?
Usually an internal seal has worn out or the housing has cracked. Bob Vila recommends replacing the unit.
Is it safe to use a leaking garbage disposal?
Water near the motor and wiring is a shock hazard. Turn it off and fix the leak first.
Related problems
Sources
This guide is general information, not a substitute for an inspection by a licensed professional. See our disclaimer.