Water Use & Conservation

Garbage Disposals

Garbage disposals are known by several names including the generic food waste disposals (FWDs),as well as waste disposal units, or garburators(Canada).

DisposalThey are an electrically-powered device, installed under a kitchen sink between one sink's drain and trap, which shreds food waste so the resulting small pieces pass easily through drain pipe. Using a garbage disposal helps keep the smells of old garbage out of your kitchen and garbage cans. Energy-wise, a typical residential kitchen garbage disposal's power demand is in the range of 350 to 400 watts but consumption is low due to the relatively short operating time.

Many standard garbage disposal units allow the dishwasher to be connected, and some dishwashers are even equipped with a small built-in garbage disposal unit, making it unnecessary to scrape plates before washing them.

Garbage disposal units are widely used in North America.

While it is claimed by some that sewage treatment plants cannot cope with the extra load of kitchen waste garbage disposal units, scientific literature does not give any proof.

New York City even banned the use of garbage disposals in the 1970s for fear that food scraps could clog up the city's sewers and threaten the Hudson River in the event of a storm overflow. NYC did an 18-month study into what effects lifting the ban might have on the city's sewers. The results showed the main benefits of increased garbage disposal use would be fewer "disease vectors" (foxes, rats, flies, cockroaches etc) in the city and less solid waste being collected and taken to landfill. In 1997, the city-wide ban on garbage disposals was lifted.

In 2003, a life-cycle analysis comparing various food waste systems, including garbage disposals,1concluded that garbage disposals do offer advantages over conventional garbage removal in terms of reduced greenhouse gas emissions, road traffic, and lower overall costs to local authorities. The study also noted how the sludge collected at a modern, upgraded wastewater treatment plant can be converted to methane and either used to generate electricity, or used as a nitrogen- and phosphorus-rich soil improver by farmers.

On the downside, the study cited higher water use - it said garbage disposals use one quart per day on average, but others say this can be as high as the equivalent to two toilet flushes per use.

Garbage Disposal Operation

  1. PeopleRun cold water whenever running the garbage disposal, as it keeps the motor and other operating parts from overheating, as well as assisting the waste to go down the drain pipe easier. Do not use hot water, because it can melt fatty substances and allow them to re-solidify as a blockage further down in the drain pipe.

  2. Do not try to put any hard items in the garbage disposal (they will dull the shredder, reduce the efficiency; and may jam the unit). Examples include:

    • large or heavy bones (very small and soft ones are okay)
    • hard seafood shells
    • un-popped popcorn kernels
  3. Avoid putting fibrous or starchy items in the garbage disposal as they also can cause stubborn drain blockages and if they are too hard, starchy or fibrous, they will jam the motor.

  4. If these items are too large, like the skins of melons, cut them into smaller pieces and put them one at a time into the garbage disposal instead of trying to shove a large amount in at once. These items should be cut into small pieces, or not put in at all:

    • banana peels
    • celery
    • potato peelings
    • corn husks
    • onion skins and egg shells (unless you're especially careful to completely remove the thin membranes of each, which can wrap around the shredder ring)
    • pasta
    • rice
    • flour
    • cornmeal
    • bread
    • Other examples include bones, meat fats, pastas, rice and potatoes (cooked or not), cheese, stringy vegetables like celery, fibrous vegetables like artichokes, corn cobs or husks, coffee grounds, egg shells, twister seals off bread wrappers, vegetable ties, glass, screws, nails, utensils, cigarette butts, avocado seeds, fruit pits, clippings off flowers, paper, plastic, children's toys, bottle caps, washcloths, melon seeds, coins, rubber bands, hair, grease, pull tabs, string or sponges.
  5. Toss in some ice occasionally (it will clean off any sharp edge debris build-up), and run cold water at the same time. Ice will not sharpen the shredders (as some believe),

Garbage Disposal Maintenance

  • Regularly Clean

    • PicUnplug or turn off the power and with the garbage disposal off, pull out the rubber device inside the sink drain leading to the garbage disposal and clean it thoroughly as it tends to get very dirty and then smell bad. Wipe it with a paper towel, reinstall, and then turn on the power.

    • Lightly turn on the hot water faucet and the garbage disposal. Let hot water go into the garbage disposal and sprinkle in a little powdered cleaner or baking soda. Turn off the garbage disposal and the water before all the cleaner is flushed away. With the mixture of powder and water scattered inside the disposer cavity and left there for a while, it will kill odor-causing bacteria.

  • Jammed Disposal

    • Turn off the power
    • Look at the bottom center of the motor for a place to insert an Allen wrench.
    • With the Allen wrench in place, manually turn the motor a few turns to get it unstuck.
    • Look for a reset or circuit breaker button on the bottom of the garbage disposal and, if there is one, press it in to reset.
    • Remove the Allen wrench before turning the power on and trying to run the motor.
  • Freshening the Disposal

    • When citrus fruits (lemons, limes, oranges, grapefruit, etc.) start getting too old for consumption (but not yet rotten), cut into pieces, place in a plastic bag, label, and freeze. Freshen the garbage disposal by periodically putting in a few frozen pieces.

  • compostConsider Composting
    • Composting is a “green” alternative to using the garbage disposal, as it saves water, energy and recycles waste that would otherwise have to be treated downstream. Done properly, the compost does not smell bad and it creates a rich fertilizer for use in potted plants or in the garden.


  • Don't put any utensils, non-food materials, fingers, or hands in the disposal.
  • Don't touch the power switch with wet hands. This can cause a shock.
  • If a septic tank is used, use a disposal very sparingly or not at all.

1 conducted by the University of Wisconsin-Madison (and partly funded by the National Association of Plumbing-Heating- Cooling Contractors).

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