Garbage Disposal Leaking? Where It Drips Tells You the Fix

A puddle under the sink gets blamed on the disposal, and often the disposal is fine — it’s the connection above or beside it. Where it leaks tells you what to fix, and only one of the answers means buying a new unit.

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Find the leak point first

Dry everything with a towel, put a dry paper towel underneath, then run water and watch. Wet paper shows you where it starts. Four places:

1. The top — where the disposal meets the sink

Water appears at the sink flange and runs down the outside of the unit. This is the most common disposal leak and the cheapest to fix: the plumber’s putty seal under the sink flange has dried out and shrunk, or the mounting assembly has loosened.

The fix is to drop the unit, scrape off the old putty, roll a fresh rope, reseat the flange and re-tighten. Nothing is broken — the seal simply aged out.

2. The side — the dishwasher hose or drain elbow

Water at the small inlet where the dishwasher hose connects usually means a loose clamp or a perished hose. At the larger discharge elbow, it’s a loose flange bolt or a failed gasket. Both are inexpensive parts, and both are far cheaper than a disposal.

3. The bottom — the reset button area or the body seam

🔴 This one is terminal. Water coming out of the very bottom means the internal seals have failed and the shell is holding water it shouldn’t. There is no gasket to replace down there. Replace the unit — and do it promptly, because water is now sitting against the motor.

4. Not the disposal at all

Check the trap, the tailpiece, and the supply connections before condemning anything. A slow drip from a trap joint above lands on the disposal and runs down it, which looks exactly like a disposal leak. See kitchen sink leaking underneath.

The parts that fix the fixable ones

• InSinkErator Quick Lock mounting flange (QLM-00, stainless) — the sink-flange and mount assembly, for when the top seal has gone or the old mounting hardware is corroded.

You’ll also want fresh plumber’s putty for the flange seal. ⚠️ Don’t skip the putty and don’t reuse the old. A thin, continuous rope, seated firmly, and wipe the squeeze-out — that seal is the entire reason the top doesn’t leak.

Before you touch anything

1. Unplug the disposal or kill its breaker. Non-negotiable.
2. Bucket under the trap — there’s standing water in it.
3. Support the unit before you release the mount. They’re heavier than they look and they drop.
4. Take a photo of the plumbing before disassembly. It costs nothing and saves guessing later.

If it’s the bottom

Replace it. Picks are in best garbage disposals and the budget in cost to replace a garbage disposal. While it’s out, this is the moment to fit new supply-side parts you’d otherwise have to come back for.

Other disposal symptoms with different causes: the reset button and jams, humming but not spinning, and dishwasher not draining if the two share a backup.

FAQ

Why is my garbage disposal leaking from the top?

The plumber’s putty seal under the sink flange has dried and shrunk, or the mounting assembly has loosened. It’s the most common disposal leak and among the cheapest to fix — drop the unit, re-putty the flange, retighten.

Can a leak from the bottom of a disposal be repaired?

No. Water from the bottom means the internal seals have failed and there’s no serviceable gasket there. Replace the unit, and don’t leave it, since water is sitting against the motor.

Do I need plumber’s putty for the sink flange?

Yes, and use fresh putty rather than reusing old. A thin continuous rope under the flange, seated firmly with the squeeze-out wiped away, is what makes that joint watertight.

If the leak is at the top of the disposal: that is the sink flange, and reseating it means fresh putty underneath. Oatey plumber’s putty.

Related guides

• Best garbage disposals
• Disposal reset button & jams
• Kitchen sink leaking underneath
• Best plumber’s putty