Fix a leaking garbage disposal
Before you buy parts for a leaking disposal, find exactly where the water is coming from. A leak at the top or side can often be fixed with a wrench or a new gasket. Water coming from the bottom usually means the disposal needs replacing. Run a little water with a drop of food coloring in it. Colored water makes a slow drip a lot easier to trace.
Three places it can leak
A disposal can leak in three places, and each one means something different. At the top, where it hangs from the sink, the seal is plumber's putty under the sink flange. On the side, there are two rubber-sealed connections: the dishwasher hose and the drain elbow that carries everything to the trap. At the bottom, there's just the metal housing, and water there means the seals inside have worn out.
Water tends to run along the outside of the unit before it drips, so a wet bottom doesn't prove a bottom leak. That's why the food coloring test in step 2 is worth the two minutes.
What fails
The ring at the top can loosen with vibration.
The seal where the drain pipe attaches wears out.
The clamp can loosen over time.
Leaks from the bottom mean the unit is wearing out.
| Where you see water | What's leaking | Fixable? |
|---|---|---|
| Top, where it meets the sink | Mounting ring loose, or the putty under the sink flange failed | Yes. Tighten the ring, or reseal the flange. |
| Side, at the rubber hose | Dishwasher hose clamp loose | Yes. Tighten the clamp. |
| Side, at the pipe going to the trap | Drain elbow bolts loose or gasket worn | Yes. Snug the bolts or replace the gasket. |
| Bottom or around the reset button | Internal seals worn out | No. Replace the disposal. |
| Only when the dishwasher drains | Dishwasher hose connection | Yes. Check the clamp and the hose for cracks. |
Find the drip, then fix it
- Unplug the disposalSwitch it off and unplug it from the outlet under the sink. If it's wired directly with no plug, turn off its breaker instead. Never reach toward the disposal with power connected.
- Find the leakDry the whole unit with a towel. Fill the sink with a few inches of water and a few drops of food coloring, pull the plug, and watch with a flashlight. The first colored drip shows you where the leak is.
- Top leak: reseal the flangeIf water comes from where the disposal meets the sink, check the mounting ring first. On most units it turns to tighten, and the small wrench that came with it fits the slots. If snugging it doesn't stop the drip, the plumber's putty under the sink flange has failed and needs redoing, which means taking the disposal down.
- Side leak: tighten connectionsSnug the clamp on the dishwasher hose and the bolts or collar on the drain elbow. If the rubber gasket at the elbow is flattened or cracked, replace it. It's a few dollars at a hardware store.
- Bottom leak: plan to replaceLeaks from the bottom of the housing, or around the reset button, mean the internal seals have failed. There's no practical repair. Put a bowl under it and plan for a new disposal.
Watch it done
- No colored drips show up in the food-coloring test
- The area under the disposal stays dry after the sink drains
- No drips at the dishwasher hose when the dishwasher drains
Top still leaking? Reseal the sink flange with fresh plumber's putty.
If the leak comes back
If the top keeps leaking after tightening, remove the disposal, clean off the old putty, and reseal the sink flange with fresh plumber's putty.
If the leak only happens when the dishwasher drains, check the dishwasher hose connection first.
Not sure how old it is? Look for a date on the label underneath. Most disposals last 8 to 15 years, and a leaking one near the end of that range isn't worth new parts.
What a pro typically charges (a rough estimate; prices vary by area): A plumber typically charges $150–$300 to fix a disposal leak, or $250–$600 to replace the unit.
Find a plumber near you