Dishwasher Not Draining? What To Check Before You Call a Plumber

You open the dishwasher, expecting clean, dry dishes—and instead you’re staring at a pool of dirty water in the bottom of the tub.

Before you panic, grab a towel, or start Googling “emergency plumber near me,” there are a few simple things you can safely check yourself.

In many homes around Greater Cincinnati and Northern Kentucky, a dishwasher that “won’t drain” is often something simple: a dirty filter, a clogged drain, or a hose issue caused by food buildup—especially rice and pasta. Every modern dishwasher has a filter that needs regular cleaning, and if it clogs, water has nowhere to go.

Step 1: Is It Really Not Draining?

First, let’s make sure you actually have a problem.
Most dishwashers are designed to hold a small amount of water around the filter at the bottom—this is normal and helps keep seals from drying out.

You likely have a drainage issue if:

• Water covers most or all of the bottom of the tub after the cycle.
• You can see an inch or more of standing water.
• The dishes are clean but the machine clearly didn’t pump the water out at the end.

Before you do anything else, try running a “cancel/drain” or “drain only” function on your dishwasher.
Sometimes a cycle is interrupted, and the machine simply hasn’t run its final drain yet.

You might want to read this article from Whirlpool:

Why is there standing water in my dishwasher?

Step 2: Start With the Filter (It’s Always the Filter)

If your dishwasher isn’t draining, the number one thing to check is the filter.whirlpool+2
Every modern dishwasher has a filter at the bottom, usually under or around the lower spray arm, which catches food particles before they get into the pump and drain hose.

Over time, that filter fills up with:

• Food scraps.
• Coffee grounds and seeds.
• Paper from labels.
• And yes—swollen rice and pasta.

When the mesh is packed full, water simply can’t pass through, and it backs up into the tub. The good news: cleaning the filter is usually quick and easy.

How to clean your dishwasher filter

1. Turn off power to the dishwasher at the switch or breaker to be safe.
2. Remove the bottom rack so you can see the floor of the dishwasher.
3. Find the filter.
   • It’s often a round or oval screen or a twist‑out cylinder, sometimes under a plastic cover or cage.
4. Remove any cover or cage, then twist or pull the filter out, following the arrows on top or your owner’s manual.
5. Rinse the filter under warm water in the sink.
   • Use a soft brush or old toothbrush to gently scrub away gunk.
   • Avoid wire brushes or scouring pads that can damage the mesh.
6. Look closely for rice and pasta.
   • These starches swell in water and often wedge tightly into the filter's tiny pores, forming a dense plug that blocks drainage.
7. Pop the clean filter back in, reinstall the cover, and run a short cycle to see if the water now drains properly.

If your dishwasher is like many we see in homes in Cincinnati and Northern Kentucky, this simple filter cleaning may completely solve the problem.

Step 3: Check the Drain Well and Sump for Food Buildup

If the filter looked pretty good—or you’ve cleaned it and still have standing water—the next stop is the drain area or “sump.”
This is the small well or opening under and around the filter where water leaves the tub.

Food debris loves to collect here, including:

• Rice and pasta that have escaped the filter and swelled up.
• Seeds, popcorn kernels, and bones.
• Paper bits, wrappers, or twist‑ties.

What to do:

1. With the filter removed, use a flashlight to look down into the drain opening.
2. Carefully scoop out any visible debris with a spoon or gloved hand—don’t push it deeper.
3. If you see a thick, mushy layer of food (often rice or pasta paste), remove as much as you can.
4. Put everything back together and try another short cycle to see if draining improves.

Starchy foods are a big problem here; they absorb water, expand, and turn into a glue‑like mass that blocks flow. That “rice cement” is something we find often when customers call us out for a “mystery” dishwasher clog.

Step 4: Make Sure Your Garbage Disposal and Air Gap Are Clear

Many dishwashers in our area drain into the kitchen sink line, often through the garbage disposal.
If the disposal is clogged or the air gap is blocked, your dishwasher's water can’t go anywhere.

Check your garbage disposal

• If your dishwasher drains into the disposal, run the disposal with cold water for 10–15 seconds to clear it.
• Never run the dishwasher while the disposal is jammed or not turning freely.

Check the air gap (if you have one)

• That little “cap” or cylinder on the sink deck by the faucet is an air gap on many setups.
• Pull the cap off and clean out any food gunk inside—rice, pasta, and other debris can clog this tiny chamber and slow dishwasher drainage.

If the dishwasher stopped draining right after you had a new disposal installed, there’s another possibility: the installer may not have removed the “knockout plug” where the dishwasher hose connects. This is a small internal plug that must be punched out for water to flow; removing it is a job for someone who’s comfortable working with disposals.

Step 5: Inspect the Drain Hose for Kinks and Clogs

Next in line is the drain hose—the flexible tube that carries water from the dishwasher to the sink drain or disposal.
If this hose is kinked or clogged, your dishwasher will struggle or fail to drain.

Simple checks you can do:

• Look under the sink and trace the dishwasher hose from the cabinet wall to the drain or disposal.
• Make sure there are no sharp bends or kinks—fix any tight bends you see.
• Confirm the hose has a “high loop” or connects through an air gap so wastewater doesn’t run back into the dishwasher.

Over time, the inside of the hose can build up grease, soap scum, and food particles.
Again, rice and pasta are common culprits—they swell, settle in low spots, and can clog a hose. Deep cleaning or replacing the hose usually means pulling the dishwasher out and is often a good time to call a pro.

Step 6: Use a Gentle Cleaning Boost (If Things Look Greasy)

If you’ve cleared the filter and drain area and things are still slow, a gentle cleaning routine can help break up light buildup.

A common, safe approach is:

1. Start with an empty dishwasher.
2. Wipe away large bits of food from the bottom.
3. Place a dishwasher‑safe cup with white vinegar on the top rack and run a hot cycle (no detergent).
4. After that cycle, sprinkle baking soda along the bottom and run a short hot cycle.

This won’t fix a solid blockage, but it can help dissolve greasy residue around the filter and drain area and freshen the machine. For heavy clogs or standing water that never moves, you’re back in “call a pro” territory.

You might want to read this article from Southern Living:

How To Clean Your Dishwasher With Vinegar And Baking Soda

Step 7: When It’s Time to Call a Plumber

You’ve:

• Cleaned the filter thoroughly.
• Checked the sump and removed debris.
• Run the disposal and cleaned the air gap.
• Looked for hose kinks and tried a gentle cleaning cycle.

If the dishwasher still won’t drain, it’s likely one of these issues:

• A failing or jammed drain pump.
• An internal check valve or drain valve problem.
• An electrical control board or sensor issue is preventing the drain cycle from running correctly.

At that point, it’s safer and more cost‑effective to call a professional plumber or appliance technician rather than trying to dig into internal parts yourself. In the Cincinnati, Northern Kentucky, and Southeast Indiana area,

The Geiler Company has been helping homeowners with stubborn clogs and dishwasher drain problems since 1885, and we offer both scheduled and 24/7 emergency service when you need it.

Step 8: Keep Your Dishwasher Draining in the Future

A few simple habits can dramatically reduce the chance you’ll see standing water again:

• Scrape, don’t pre‑rinse, but be smart about food waste.
  • Scrape off heavy food, especially rice, pasta, beans, and fibrous peels, into the trash instead of letting them accumulate in the dishwasher and drain line.
• Clean the filter regularly.
  • For most homes, once a month is a good starting point; more often if you cook a lot or see debris in the bottom after cycles.
• Run hot water at the sink for a few seconds before starting a cycle so the dishwasher begins with truly hot water, helping break down grease and detergent.

If you remember nothing else, remember this:
Every dishwasher has a filter, and cleaning that filter—plus keeping rice and pasta out of the drain—is the easiest way to keep your dishwasher draining the way it should.