A leaking garbage disposal
A leak under the sink near your disposal comes from the sink flange, dishwasher hose, drain outlet or a cracked body.
Updated · 3 min read
If you read one thing
Fill the sink with colored water, then run it and watch from below. Drips at the top mean the sink flange seal; at the side, the dishwasher hose or drain outlet; at the bottom, a cracked housing that means replacement.
In this guide
Find the leak with dye
Put a few drops of food coloring in a sink of water. Dry everything under the sink with a towel, then pull the stopper.
Watch the disposal with a flashlight. Colored drips show which joint leaks.
Top: the sink flange
The flange is the metal ring in the sink drain. It seals with plumber's putty or a gasket. When the mounting loosens, water seeps between the sink and flange.
Tightening the mount or resealing the flange stops it.
Side: hoses and drain outlet
The dishwasher hose clamps onto a port on the side. The drain outlet elbow connects with a gasket and flange.
Loose clamps and worn gaskets are common and straightforward to replace.
Bottom: the housing
Water from the bottom or around the reset button means the internal seal has failed. That leak cannot be repaired, and the unit needs to be replaced.
Half of Alhambra homes date from about 1960 or earlier, per Census Reporter, so disposers there were added later, and cabinet space can be tight. Measure before buying a larger unit.
Alhambra homeowner questions
Can I use plumber's putty on a leaking flange?
Yes, when resealing the flange. It does not fix a cracked housing.
Why does my disposal leak only when the dishwasher runs?
The dishwasher hose connection or clamp is the likely source.
Is a leaking disposal safe to keep using?
Turn it off if water reaches the electrical connection underneath. Otherwise, limit use until repaired.