Most disposal trouble shows up as one of six symptoms. Here’s what each one usually points to, what you can safely check yourself, and when it’s our turn.
It hums but the blades don’t turn
A hum means the motor is getting power but the grinding plate is stuck, usually on a bone, a fruit pit, a bottle cap or a utensil that slipped in. Running it longer won’t clear it; the motor heats up until its overload protector shuts it off. InSinkErator’s fix starts with the switch off: put the wrench that came with the unit, or a 1/4-inch hex key, into the socket in the center of the bottom of the disposal and work it back and forth until it turns full circles both ways. Then look in with a flashlight and lift the object out with tongs or pliers. Waste King’s instructions use a wooden spoon or unjamming wrench on the turntable from above, again with the power off. Both makers say the same thing about hands: never put yours inside the disposal.
It does nothing at all
Silence at the switch is usually the overload protector. On most units it’s a small red button on the bottom, facing the floor; when it has tripped it sits a little lower than usual. Press it gently. InSinkErator says if it won’t stay in, wait about ten minutes and try again; a unit that won’t restart may need up to 20 minutes to cool. Disposals started by a push button on the countertop (an air switch) can be unplugged for that time instead. Still nothing? Check the breaker. If the reset is fine, the breaker is on and the plate turns freely, the problem is the motor or the power to it, and your technician will tell you which.
Water under the sink
Dry everything with paper towels, run some water, and find where the drip starts. InSinkErator sorts disposal leaks by place, and each one means something different:
At the top, where the unit meets the sink: the sink flange or mounting assembly. The seal under the flange has dried out, or the mount has loosened from vibration. We reseat it.
At the dishwasher hose: a loose clamp or a cracked hose on the inlet at the side of the unit.
At the side outlet pipe (the discharge): a worn gasket or a loose bolt or nut where the drain pipe connects.
From the body or the bottom: the water is coming from inside the unit. That isn’t a connection we can tighten, and it usually means a new disposal.
Slow draining, or water backing up into the other sink
A disposal that grinds fine but leaves standing water, or a double sink where one side fills when the other drains, usually has a clog in the pipe past the disposal, not in the disposal itself. Starchy and fibrous scraps, grease and coffee grounds pack into the trap and the line behind the wall. Don’t pour chemical drain cleaner into a disposal; Waste King lists caustic drain cleaner among the things to keep out of it. Clearing that line is a drain cleaning call, and we check the disposal while we’re there.
A bad smell
Odor usually means food has built up in the grinding chamber and on the underside of the rubber splash guard. InSinkErator’s steps: turn the disposal off and disconnect its power, scrub the underside of the splash guard and the upper lip of the chamber with a scouring pad, then fill the sink halfway with warm water and a quarter cup of baking soda and run the disposal as you pull the stopper. A smell that comes back right after cleaning can be a slow drain holding waste in the line.
What to keep out of it
Waste King’s list of things never to put down a disposal includes large whole bones, clam and oyster shells, glass, china, plastic, bottle caps, foil, utensils, caustic drain cleaner, and hot grease or other hot liquids. InSinkErator says never fats, oils or grease, and to feed scraps gradually rather than all at once. Coffee grounds and eggshells won’t hurt the unit, InSinkErator says, but they can clog older or narrow drain lines, so add them slowly with a strong flow of cold water. Run cold water while it grinds and for a few seconds after.
Grease is the big one in Houston. Houston Public Works says about 70% of sewer overflows in the city come from clogs caused by fats, oils and grease poured down drains. The City’s advice: wipe greasy pans and plates with a paper towel before washing, throw the towel in the trash, and use a sink strainer.
Choosing a size: horsepower in plain terms
Horsepower is how much grinding muscle the motor has. More of it handles tougher scraps and bigger loads without stalling; the larger motors are also physically bigger, so the cabinet space under the sink matters. Moen’s sizing chart suggests 1/3 or 1/2 horsepower for one or two people, 1/2 or 3/4 for three to six, and 3/4 or 1 for five to eight, and notes the higher-horsepower models grind a wider variety of scraps. There are two feeding styles as well: continuous feed runs as long as the switch is on, and batch feed runs only with its stopper in place. Your technician will look at your sink, cabinet and dishwasher hookup and tell you what fits.
Sources: InSinkErator, fixing a jammed garbage disposal · InSinkErator, garbage disposal leaking · InSinkErator, odor coming from a disposal · InSinkErator, what not to put in a garbage disposal · Waste King, support FAQs · Moen, choosing a garbage disposal · Houston Public Works, Protect Our Pipes. Checked November 2026.
