Why is my garbage disposal leaking?
Updated August 2026
Where a garbage disposal leaks is the whole diagnosis, and the most likely spot is the sink flange at the top, where the plumber's putty under the collar has dried out and let water seep down the mounting. Re-seat and re-putty that flange first, since it is a few-dollar fix. A leak from a hose or the drain gasket is next most likely, and only a drip from the very bottom center points at the sealed motor, which cannot be repaired. Dry everything, run water, and trace the first drop to its highest point.
Safety first: before you reach under a wet disposal, unplug its cord or switch off its breaker; a plugged-in motor sitting in standing water under the sink is a shock risk, and the impellers can pinch fingers even with the power off.
Causes, most likely first
| Cause | How likely | The fix | Typical cost |
|---|---|---|---|
| Sink-flange seal at the top | Most common | Loosen the mounting ring, re-roll fresh plumber's putty under the flange lip, re-seat and snug it back down. | $0–15 putty |
| Dishwasher drain-hose connection | Common | Tighten the hose clamp or replace the ribbed rubber connector where the dishwasher hose enters the disposal inlet. | $5–20 |
| Drain-outlet gasket and discharge tube | Common | Replace the flange gasket and rubber washer, then re-snug the metal band clamp at the discharge elbow. | $5–30 |
| Failed internal seal (leak from bottom center) | Occasional | Water from the lowest point near the reset button is the motor seal; the unit is done, so replace it. | $150–450 installed |
| Cracked housing from age or corrosion | Rare | A hairline split in the body weeps under load; there is no patch, so swap the disposal. | $150–450 |
Check these first
- Dry the disposal, the drain arm, and the cabinet floor with paper towels so any new water shows exactly where it starts.
- Fill the sink, then pull the stopper and watch the flange collar and drain elbow as it empties; a drain leak only shows under full flow.
- Run the dishwasher a cycle and watch the ribbed hose connection, since that leak appears only mid-cycle.
- Shine a light on the red reset button underneath: water dripping from the bottom center points to the sealed motor, not a fitting.
- Wiggle the discharge tube where it meets the P-trap; loose slip nuts there can fake a disposal leak.
Prevent it next time
The habit that heads off most disposal leaks is catching them early and retiring the unit before its seals give out. Snug the sink-flange mounting ring and glance at the cabinet floor whenever you clean the disposal, and remember these units run 8–12 years before internal seals fail, tracked on our disposal replacement schedule. A dry paper towel taped under the unit turns the next slow drip into a same-day catch instead of a warped cabinet base.
When to call a pro
Call a plumber when the leak comes from the bottom center of the disposal: that is the sealed motor housing, and no gasket or putty fixes it, so the unit gets replaced for $150–450 installed. Also call if the mounting assembly is corroded or the sink flange spins freely. A flange re-seal or a hose-clamp swap is a 20-minute DIY, but a dead unit that also will not turn on is worth replacing rather than repairing.
Most of the causes above are maintenance problems wearing a disguise. OnOtto keeps the boring prevention on schedule so the 2 a.m. version doesn't happen.
Stop chasing symptoms, free for 30 daysFrequently asked questions
Can I keep using a garbage disposal that leaks?
For a top-flange or hose leak, yes, for a few days while you reseal it, as long as you dry the cabinet and keep an eye on it. A bottom-center leak is different: that water is coming through the motor seal, so every use pushes more into the cabinet and closer to the wiring. Shut the disposal off at the breaker, set a bucket under it, and replace the unit within a day or two before the leak warps the cabinet base or reaches an outlet.
How do I tell a flange leak from a bottom-seal leak?
Dry the whole unit, then fill the sink and let it drain while you watch with a flashlight. Water appearing at the top collar where the disposal meets the sink is a flange leak, fixed with fresh plumber's putty for a few dollars. Water dripping off the lowest point, near the red reset button, is the internal seal, which means the disposal is finished. Location is the entire diagnosis here, so trace the first drop back up to its highest point.
How much does it cost to replace a leaking garbage disposal?
A new 1/2 to 3/4 hp disposal runs $80–250 for the unit, and a plumber's labor adds $80–200, so a full replacement lands around $150–450 installed. Doing it yourself drops the cost to the price of the unit plus a $10 tube of plumber's putty. If the old mounting assembly is in good shape, a same-brand swap can take under an hour, since the sink flange and mounting ring often carry over.
Is plumber's putty or silicone better for sealing the flange?
Plumber's putty is the standard for a disposal sink flange because it stays pliable and lets you remove the flange later without a fight. Roll a rope of putty under the flange lip, seat it, tighten the mounting ring, and wipe the squeeze-out. Use silicone only where the maker calls for it, or on certain stone and composite sinks that putty can stain. Either way, let it set before running water, and re-snug the ring after the first day.