Your Garbage Disposal Could Be Making Your Clean Dishes Dirty—Here's How To Stop It

Don't let a little plumbing snafu make your dishwasher filthy.

Kitchen Sink Disposal with Water Draining Down
Photo: Getty/-Oxford-

The garbage disposal is one of those kitchen conveniences that you never think about, unless something is wrong. When your garbage disposal acts up or won't turn on, it can quickly fill up with bits of food food, and in some cases, the food can back up into your dishwasher.

If this sounds like a disgusting mess, there are a few simple things you can do to treat your garbage disposal and avoid having to call a professional.

Too Much Food Can Block the Drain

Tommy Holland, a handyman in Savannah, Ga., fixes the common issues that constitute big emergencies for most homeowners. He’s multi-talented, serving as a problem solver for kitchen disasters and also playing a musical Santa Claus during the holidays.

When he isn’t strumming his guitar or granting the wishes of children, he’s usually knee deep in plumbing problems for his clients. When he’s called to fix a garbage disposal, he likes to start with a little homeowner education.

"You really shouldn’t put anything into your garbage disposal,” he says. “Scrape your plate into the trash can. It’s not a grinder for all food."

While we all have made the mistake of confusing our garbage disposals as a one-stop refuse solution, there are some items that just spell a disaster and absolutely should not be in the sink.

Coffee grounds, eggshells, grease, or the pits of fruit aren’t garbage disposal-friendly. Potato peels and pasta create a sticky mess that affects the movement of the shredder. It’s these items that can ruin a garbage disposal's mechanics and cause liquid refuse to enter your dishwasher. Holland also advises lettuce, leafy vegetables, and anything with a string should stay away from the sink.

The reason? The disposal process begins by forcing food into an impeller, which doesn’t grind. Instead, impellers, sometimes called lugs, are attached to a plate that spins, and it tears the food apart. Powerful models can reduce the food to a liquid, which travels out of the drain easily.

But with weaker garbage disposal motors, hard pieces of food can become trapped and block the drain.

Blockages Lead to Stinky Sinks and Dirty Dishes

Once a blockage occurs, you now need to be worried about your dishwasher—and your disposal, too, of course.

During a cycle, a dishwasher drains from either a drainpipe or it empties straight into the garbage disposal in your sink. If there’s a blockage, that nasty clog can prevent the water from getting to the garbage disposal, and all the water can back up into your clean dishes. 

Holland knows the solution from here: “When you have a backup, you can remove the p-trap under the sink and clean it out. You want to flush out the gunk as much as you can.”

A p-trap is more than just a drain. The u-shaped pipe creates a pathway for water to exit your home and head to the sewer. It also protects the house from methane gas that might rise from the sewer, if it wasn’t trapped in this area.

The bed in the pipe is also handy to catch small items that accidentally go down the drain. Unfortunately, that also creates a great location to catch pieces of food and develop a clog.

Since a leaking p-trap is a big problem, Holland is often called to clean the trap and reinstall it to prevent issues. 

“Run hot water in both sides of your sink, as much as you can. That will help with oil and debris,” Holland cautions, “And turn your disposal on and run it. If you aren’t flushing that debris, it can get gummed up. Try to keep it spinning and throwing the food through.”

Holland’s advice is solid. Keeping the unit moving will prevent many disasters. By following a few methods and really watching what you put down that disposal, you may avoid seeing dirty water appear where you wash your cups.

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