Garbage disposal leaking from the bottom: the four places it leaks, the newspaper test that finds which one, and the one case InSinkErator says to call about

Three of the four places a disposal leaks are a tightening or a gasket, and the fourth is a phone call before it is a purchase.

Where is the water actually coming from?

Read InSinkErator’s locations from the top: water from the sink flange runs down the outside of the unit and ends up at the bottom, which is why the bottom is the wrong place to start.

The mounting assembly is the ring of parts that clamps the sink flange to the sink and hangs the disposal from it; the discharge outlet and dishwasher inlet are the two side ports.

How do you find the leak?

Cut the power first. The Badger manual’s removal step is headed shock hazard and says to turn off electric power at the circuit breaker or fuse box, and its grounding section says to disconnect power before servicing the disposer. The wall switch alone is not enough.

InSinkErator’s method for a hard-to-find leak, in the leak page’s order:

1. Empty the cabinet and dry the outside of the disposal.
2. Spread newspaper flat over the cabinet floor and tape it down.
3. Stopper and fill the sink, leave it full for a while, then look for a wet spot.
4. Pull the stoppers, let it drain, and look again.
5. Run the water and the disposal while you look a third time.
6. If nothing shows, leave the paper for a few days.

The stage that first marks the paper is your table row. If it never marks, InSinkErator says to check water filters, the dish sprayer, the faucet, the dishwasher drain hose and the sink and countertop seams. No maker or extension page opened for this article prints a dye or food-colouring test, so this page does not describe one.

What does each fix involve?

Sink flange. The mounting-assembly page says leaks there typically come from installation: rotate the locking ring fully to the right and tighten all three mounting screws. On a new install, excess putty under the flange is a named cause, fixed by removing the disposal, clearing the excess, retightening and remounting. The Badger manual’s figure for a fresh seal is a 1/2 inch thick rope of plumber’s putty around the flange. If the fiber gasket or the pleated mounting gasket (on some models) is damaged, the InSinkErator MGK-00 mounting gasket kit is the maker’s part; check the fit on the InSinkErator model cross-reference.

Dishwasher inlet. Tighten the hose clamps and check the hose adapter is intact and the elbow-to-trap joint tight. The knockout plug inside the inlet must be out before the hose goes on.

Discharge outlet. The Badger manual seals this joint with one gasket inserted into the outlet and two bolts. The discharge page says to tighten the bolts, then check the gasket for debris, cracks or rips and the elbow for a crack. A third-party drain elbow kit with gasket replaces elbow, flange, gasket and screws together; it is not an InSinkErator part, and its listing title names the 1.5 inch size.

One rule covers all three: the Badger manual’s notice says no plumber’s putty on any connection other than the sink flange, and no thread sealants or pipe dope, because these may harm the disposer and cause property damage.

When is it the housing?

InSinkErator’s leak page gives three locations no user fix: the bottom, the container body wall and the motor joint. For the first two it asks you to confirm the water is not running down from the mounting assembly; for all three it says to contact the company. It does not say the unit must be replaced, so the published fix list ends there and the next question is the warranty.

The Badger manual prints the in-home full-service limited warranty by model: defects in materials or workmanship in residential use, parts and labour included, and only an authorized InSinkErator service representative may provide warranty service.

Evolution units are covered by their own manual, so their term is not printed here. Past the warranty, a confirmed housing leak is a replacement. The Badger 5XP is the same series with a 6 year term, the Evolution 1 HP the Evolution series, and the Waste King L-1001 a different make, with no Waste King term quoted here. The best garbage disposal page compares them on published specs.

What should you do first?

1. Switch off at the wall, then at the breaker or fuse box, and unplug a corded unit.
2. Dry the disposal and tape newspaper flat under it.
3. Fill, wait, drain, then run water and the disposal, checking the paper after each stage.
4. Tighten what the matching row names: locking ring and three screws, hose clamps, or the two discharge bolts.
5. Replace only the gasket the paper points at, with putty at the sink flange alone.
6. If the mark is under the housing, body wall or motor joint, call InSinkErator with the model and purchase date first.

Frequently asked questions

Sources

1. InSinkErator, Garbage Disposal Leaking (manufacturer or vendor document)
2. InSinkErator, Garbage Disposal Leaking from the Mounting Assembly (manufacturer or vendor document)
3. InSinkErator, Garbage Disposal Leaking at the Discharge (manufacturer or vendor document)
4. InSinkErator, Garbage Disposal Leaking at the Dishwasher Inlet (manufacturer or vendor document)
5. InSinkErator, Badger Series Installation, Care and Use Manual (PDF) (manufacturer or vendor document)