What Do Plumbers Say About Garbage Disposals?

The short version of plumber advice

Ask plumbers about disposals and you will hear mixed opinions, but a common thread runs through them. A disposal can work well in a home with a healthy drain line, and it causes trouble when people treat it as if it can handle anything.

The key point is that a disposal only chops food into smaller pieces. It does not make those pieces disappear. Everything it grinds still has to travel through your kitchen drain, your home's pipes and, in some homes, a septic system. A disposal that runs fine can still feed a drain that is struggling.

Some plumbers prefer that households scrape plates into the trash or a compost bin and use the disposal only for small leftovers. Others are happy to see a disposal installed, because it can keep large scraps out of the trap. Both views agree on one thing: how you use it matters.

What plumbers tell you to keep out of the disposal

This is the part of plumber advice that stays the same no matter who you ask. Certain foods either damage the unit or collect in the pipes and cause slow drains.

• Grease, fat and cooking oil. They cool and coat the inside of pipes, then trap other debris.
• Bones, fruit pits and shells. These are hard enough to dull or jam the grinding parts.
• Stringy or fibrous food such as celery, corn husks and onion skins. The fibers can wrap around the grinding parts and tangle in the drain.
• Starchy foods in large amounts, including rice, pasta and potato peels. They swell and turn into paste.
• Coffee grounds in bulk. They pack together in the trap and can form a sludge.
• Non-food items, including glass, metal, plastic and cleaning wipes.

Why the drain matters as much as the disposal

A disposal can handle a food scrap that your drain line cannot. Older pipes, long horizontal runs and pipes with a shallow slope all give food particles more chances to settle and build up. If your sink already drains slowly, a disposal will not fix that and may make it worse.

If you have a septic system, check the manufacturer's guidance and your septic service provider's advice before relying on a disposal. Several units in our data are listed as septic safe, but that label does not mean you can send unlimited food waste to the tank.

Plumbers also point out that a disposal will not stay fresh without help. Food residue can sit on the grinding parts and cause odors, so regular rinsing and light cleaning are part of normal ownership.

Habits that plumbers recommend

These steps are simple, and they are the ones most often cited for keeping a disposal and its drain in good shape.

• Run cold water before, during and for 15 to 30 seconds after grinding, so the pieces flush through the pipes.
• Feed scraps in gradually instead of dumping a full bowl at once.
• Cut up large scraps into small pieces first.
• Let the disposal finish its work before you shut off the water. If you hear a hum with no grinding, switch it off.
• Clean the splash guard or baffle with a brush and dish soap from time to time.
• Keep the disposal for soft scraps and put fats and bones in the trash.

What to look for if you are choosing one

If you decide a disposal makes sense, a few specifications separate a basic unit from a better one. Our garbage disposal comparison page puts the published specs of several models side by side, so you can match one to your kitchen and household.

Motor power is the first thing to check. The models on our page range from 1/2 to 1 HP, and a bigger motor generally handles tougher scraps and busier kitchens. Grind stages matter too, because more stages break food down finer before it enters the drain. The models here have 1 to 3 stages.

Then check whether a power cord is included, what mount type it uses, and how long the warranty runs. If you are replacing an old unit, matching the mount makes the swap easier. The table below shows a few examples from the published data. A dash means the spec is not listed in our data.

Matching a disposal to the advice

Plumber advice leans toward models that grind finely, since finer particles are less likely to stick in the pipes. On our page, the Evolution stands out for grinding, with a 3-stage grind and sound insulation. The Power Series 1 HP is the most powerful option listed, with a 2-stage grind.

If you want a longer warranty, the Waste Maid 158 lists 8 years, and the GE Disposall lists 7. Either is a simpler unit with a 1/2 HP motor. You can see how the rest stack up on our disposal comparison, including the cord and mount details that affect installation.

Keep in mind that a stronger disposal does not remove the need for good habits. The same list of foods to avoid applies to every model.

Safety notes

Disposals have powerful moving parts, and the wiring is under your sink, where water is close by. A few precautions are worth following every time.

• Never put your hand into a disposal, even when it is off. Use tongs or pliers to remove an item.
• Turn off the wall switch and unplug the unit before clearing a jam. If it is hardwired, switch off the breaker.
• Use the jam-clearing wrench that comes with some models only after the power is off.
• Do not pour drain cleaners into a disposal unless the manufacturer says it is safe. Chemicals can splash and damage parts.
• Wear eye protection when working under the sink, since debris and drips can fall toward your face.
• If you are not comfortable with wiring or plumbing, hire a licensed professional for installation.

Frequently asked questions

Do plumbers recommend installing a garbage disposal?

Many do, with conditions. They tend to be comfortable with one in a home with healthy drains, as long as the household avoids grease, bones and fibrous food.

Why do some plumbers dislike disposals?

The main complaint is that people overuse them. Food waste, grease and starch can build up in pipes and lead to clogs and odors, which then bring service calls.

Is it okay to use a disposal with a septic tank?

It depends on your system. Check the disposal maker's guidance and ask your septic service provider before you rely on one.

Should I use hot or cold water when grinding?

Cold water is the usual advice. It keeps fats solid so they are chopped and flushed, instead of melting and coating the pipes.

What should I do if my disposal hums but does not grind?

Switch it off at the wall, unplug it or turn off the breaker, then clear the jam with tongs or the wrench that came with the unit. Restore power and test it with water running.