To maintain a garbage disposal so it lasts, use cold water every time, feed scraps gradually, and keep grease, glass, metal and large bones out. Never oil the motor or add lye or chemical drain cleaner, since makers say both cause damage. Wipe the splash guard when it smells, and act early on jams and leaks.
What should you do every time you use it?
The makers agree on the daily routine, and it is short.
- Cold water first. InSinkErator's steps are to turn on cold water, turn on the disposal, feed food waste in gradually, wait for the grinding to stop, let the water run a few seconds, then turn off the disposal and the water. Waste King says to let the water and disposal run about 15 seconds after shredding stops, so the waste is flushed through the trap and drain. Our page on whether to run hot or cold water covers why.
- Do not pre-load it. InSinkErator says "Do NOT pre-load the disposal."
- Keep the stopper in. Waste King says to leave the stopper in place when the disposal is not running, so utensils and other objects do not fall in.
- Empty it before the dishwasher runs. Waste King says to make sure the disposal is empty before you use a dishwasher that drains through it, so the dishwasher can drain properly.
- Keep grease out. InSinkErator says to never pour grease or fat into the disposal or drain, and its food list repeats the warning for every series.
What should you keep out of the disposal?
Moen lists items that can damage the unit or be thrown back at you: large whole bones, clam or oyster shells, whole corn husks, glass, china, plastic, metal such as bottle caps, tin, aluminum foil and utensils, and hot grease or other hot liquids. Waste King's list adds plastic, leather, cloth, rubber, string and feathers, and says these items may damage the disposal and the plumbing system. For the foods people ask about most, see our pages on coffee grounds and eggshells, rice and pasta.
### What should you never put on or in the motor?
Two products come up. Both makers warn against them in strong terms.
- Lubricant. Waste King says "DO NOT ATTEMPT TO LUBRICATE YOUR DISPOSAL!" It says the motor is permanently lubricated and that the disposal is self-cleaning, scouring its internal parts with each use. Moen's warranty text says not to attempt to lubricate the product.
- Lye and caustic drain cleaners. Waste King says never to put lye or chemical drain cleaners into the disposal, because they cause serious corrosion of metal parts. Moen says the same. It calls this improper maintenance that may corrode metal parts, and it says the damage is detectable and not covered by the warranty.
If the sink is clogged, do not reach for the chemical bottle. A plumber can clear it with a cable or a jet without harming the unit.
How do you keep it clean and odor free?
Water flow is most of the answer. InSinkErator says an odor from the disposal "is usually a sign of food buildup, caused by insufficient water flow during and after use." Waste King says most odors come from food building up on the splash guard over time.
Their cleaning steps are simple.
- 1Turn off the disposal and the power. InSinkErator says to disconnect the power supply, and never to put your hand in the disposal.
- 2Scrub the underside of the splash guard, or the baffle, with a scouring pad and a little baking soda and warm water.
- 3Rinse. Waste King says to turn on warm water and let it run to rinse the splash guard. InSinkErator's method is to fill the sink halfway with warm water and 1/4 cup of baking soda, then turn on the disposal while lifting the stopper to wash away loose particles.
Waste King adds that on its EZ Mount units the splash guard is removable and can go in the dishwasher, while on its 3-bolt professional mount the guard is built in and cannot be removed. The stopper, on the other hand, does not go in the dishwasher, according to its batch-feed instructions. Our page on why a garbage disposal smells bad covers the smell itself, including when the source is not the disposal.
### Is the rust on the turntable a problem?
Probably not. Waste King says mineral deposits from your water can form on the stainless steel turntable and look like rust, and that the stainless steel turntable will not corrode or rust. Do not be alarmed.
### What does a simple yearly check look like?
You do not need a schedule from the maker, since none of the sheets gives one, but a short check a few times a year catches trouble early. This checklist is our suggestion, built from the makers' own rules.
- 1Look under the sink with a flashlight. Check the flange, the discharge elbow and the dishwasher inlet for drips or stains, the way InSinkErator's leak guide describes.
- 2Wipe the splash guard. Use the scouring pad and baking soda method above.
- 3Run it with cold water. Listen for the smooth grind that the makers describe, and stop if you hear metal on metal.
- 4Check the switch and the outlet. Waste King and Moen both call for a dedicated switch within sight of the sink, so make sure it works and the cord is not damaged. Moen says a damaged supply cord must be replaced with a cord assembly from customer service.
- 5Confirm the model and serial number are written down.
What warning signs should you act on early?
Small problems are cheaper to fix than large ones. Watch for these.
- A jam. Waste King lists three signs: a noise that is not the normal grind, visible waste at the splash guard or flange after running it, and the smell of rotten food from the opening. If it hums, see why a garbage disposal hums but will not work.
- A tripped reset. If the unit goes dead, the red reset button is the first thing to check. Our page on where the reset button is shows each brand.
- Water under the sink. A leak at the flange, discharge or dishwasher inlet is easier to fix early. InSinkErator says to check the top of the unit first, because water travels. See why a garbage disposal leaks.
- A slow sink. A slow drain is often the line, not the disposal. Our page on why a garbage disposal drains slowly helps you tell the difference.
How long should a disposal last, and when do you replace it?
The warranty is the only lifespan number a maker will put in writing, and it varies by model. Waste King's sheet lists two years for some models and up to twenty years for others. Waste King asks owners to write down the model and serial number and keep proof of purchase, and Moen says the numbers are on the engraved plate on the bottom of the unit. Write them down now so a warranty claim is easier later.
Replace it when a body or motor-joint leak appears, when the unit trips over and over, or when repairs stack up. InSinkErator sends body and motor-joint leaks to the manufacturer, which tells you they are not a home repair. Our page on how to replace a garbage disposal walks through the swap, and what size garbage disposal you need helps you pick the next one.
### When should you call a plumber?
Call one for a leak you cannot trace, a disposal that trips or jams again and again, or a sink that backs up. HQ is licensed and insured, offers 24/7 emergency service, and gives free estimates and upfront pricing.