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ADRIUM Service Solutions
(925) 999-4095 · San Ramon, CA · CSLB #1136642 · BBB A+

Troubleshooting

Dishwasher Not Draining: Filter, Pump, and Air Gap

Standing water in your dishwasher after a cycle points to one of a few culprits. Here's how to tell whether it's a quick filter clean or something that needs a tech.

By May 30, 2026 4 min

A dishwasher that finishes its cycle and leaves a pool of dirty water is one of the most common calls we get. About half the time it’s a clog you can clear yourself. The other half needs a tech. Start with the easy stuff.

One note first: a small amount of clean water sitting in the sump (the recessed well at the bottom) is normal. It keeps the pump seals from drying out. The problem is an inch or more of cloudy water that won’t go away after a full cycle.

Start with the filter

Most modern dishwashers have a removable filter in the floor of the tub, under the bottom spray arm. Food, grease, and broken glass collect there. When it packs solid, water can’t reach the drain.

Pull the bottom rack out. Twist the cylindrical filter counterclockwise and lift it free. Rinse it under hot water, scrub the mesh with an old toothbrush, and clear any debris from the opening underneath. Drop it back in and lock it. This single step solves a large share of no-drain complaints, and it’s the first thing we check on a service call.

Check the garbage disposal and air gap

Your dishwasher drains into the same plumbing as your kitchen sink. Two things on that path cause trouble.

If you have a garbage disposal, the dishwasher hose connects to it. New disposals ship with a knockout plug in that inlet; if a recent install left it in, the dishwasher has nowhere to drain. Run the disposal to clear any food packed at the connection, then see whether water moves.

The air gap is the small chrome cylinder on the back edge of the sink, next to the faucet. Pop the cap off, unscrew the cover, and look for sludge inside. Clean it out. A clogged air gap will leave water in the tub and sometimes spit it onto the counter.

Drain hose and pump

If the filter, disposal, and air gap are clear and water still sits, the drain hose or the pump is the problem. Both need a tech.

The drain hose runs from the pump under the sink. A kink can stop flow, and so can years of grease narrowing the inside. The hose is supposed to loop up high before it drops to the disposal; if that loop slips down, water siphons back into the tub. Clearing an internal clog or re-routing the hose means pulling the lower access panel and disconnecting plumbing. It’s easy to get wrong, and a slow leak you don’t notice for a week can do a lot of cabinet damage.

The drain pump is what physically pushes water out at the end of a cycle. A shard of glass or a fruit pit can jam the impeller; a burned-out motor will hum without moving water. Testing it means checking the impeller and motor windings with a meter. That’s live electrical work near water, and a pump replacement on most brands runs $90 to $220 in parts alone. Worth getting it done right.

A Dishwasher Pump and Sump Leak, On Camera

The base of a Whirlpool-family dishwasher (Whirlpool, KitchenAid, Maytag), where the circulation pump, sump, and diverter live. A worn pump seal, a cracked sump, or the diverter lets water past and onto the floor.

When to call ADRIUM

Clean the filter, run the disposal, and clear the air gap yourself. Those take twenty minutes and need no tools. If the water stays put after all of that, call us. Same if you hear the pump straining, smell burning, or get a drain error code that won’t clear.

For a broader rundown of dishwasher faults (leaks, heating, control boards) see our dishwasher repair guide, or read about our dishwasher repair service.

We service Bosch, KitchenAid, Whirlpool, Samsung, LG, and more across the Tri-Valley. We’ll get you on the schedule fast, often same or next day when slots are open. Flat diagnostic fee, credited toward the repair when you book the work. CSLB #1136642, BEAR #50788, A+ with the BBB, in business since 2021.

Call (925) 999-4095 or email [email protected]. You can also reach us through the contact page.

FAQ

Why is there standing water in the bottom of my dishwasher? A shallow pool of clean water in the sump is normal. An inch or more of dirty water that won’t drain points to a clogged filter, blocked hose, plugged air gap, full disposal, or failed pump.

Can I run my dishwasher if it won’t drain? Not a full cycle. Clear the clog first, run a short rinse to test, and stop if it still holds water so you don’t flood the cabinet.

How often should I clean the filter? Monthly for a busy kitchen, every two to three months if you rinse plates first. It twists out by hand.

FAQ

Common questions.

Why is there standing water in the bottom of my dishwasher?
A shallow pool of clean water in the sump is normal. An inch or more of dirty water that won't drain after a cycle means something's blocking the path: a clogged filter, a plugged air gap, a full garbage disposal, a kinked hose, or a failed drain pump. The filter, air gap, and disposal are safe to check yourself. If those are all clear and water stays, call us.
Can I run my dishwasher if it won't drain?
Don't run a full wash cycle until it's draining again. Water that can't leave will overflow onto the floor or sit and grow bacteria. You can run a short rinse to test after you clear a clog, but if it still holds water, stop and have it looked at before you flood the cabinet.
How often should I clean the dishwasher filter?
Once a month for a busy household, every two to three months if you rinse plates before loading. The filter sits in the floor of the tub and twists out by hand. Most no-drain calls we get in the Tri-Valley trace back to a filter nobody knew existed.
Is a dishwasher that won't drain worth repairing?
Almost always, yes. A drain pump runs $90 to $220 in parts on most brands, and a clog clears for the price of the diagnostic. Replacing the whole machine over a drain problem rarely makes sense unless the unit is past 10 years old and has other failures stacking up.

Got a real problem?

Tell us what's broken. We'll quote it.

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