Dishwasher Not Draining? 5 Causes, Free Checks and Fixes

A dishwasher that will not drain is a blocked drain path far more often than a dead pump. In most Arizona kitchens the fix is the filter, the hose, the disposal plug or the air gap, and all four can cost nothing. A pro visit runs $100 to $300 when it is the pump.

This guide checks things in the order a repair tech does, so you stop at the first fix. Each step says how to test it, what it costs here, and whether to do it yourself.

• Unplug the dishwasher or flip its breaker, then scoop out the standing water.
• Twist out the filter at the bottom of the tub and rinse it. This is the fix about half the time.
• If you just had a new disposal or dishwasher installed, check that the knockout plug inside the disposal inlet was punched out.
• Look under the sink for a kinked, crushed or sagging drain hose, and for a high loop.
• If you have a chrome air gap by the faucet, pull the cap and clean it.
• Still full of water after all that? The pump or the control board is next, and that is a pro job.

Do these in order. They take about 5 minutes each and need no tools beyond a towel and a screwdriver. Safety first. Turn the breaker off for the dishwasher, because Whirlpool says not to rely on the control panel alone.

Is the cycle really finished? Frigidaire says to make sure the cycle is done and not sitting in pause.

How much water is normal? GE Appliances says 1 to 2 cups of clean water in the bottom is normal on models without an ultra fine filter. On models with one, water in the filter area is normal but it should not cover the floor of the tub. An inch of gray water is not normal.

Run the disposal. If your dishwasher drains into a disposal, run it for 20 seconds with water on. GE says to always run the disposer before a cycle to clear the drain path. Never put your hand in to check it.

Look for a new install. If the disposal or dishwasher is less than a few weeks old, jump to the knockout plug section below. It is the most common cause on new installs.

Skip the drain cleaner. GE says not to pour drain cleaner into the dishwasher. It will not fix a hose clog and can harm parts.

What it is. Food bits, labels, seeds and glass slivers pack into the filter at the bottom of the tub. Bosch lists slivers of glass, food and dirt as a common reason a dishwasher stops draining. Our cost box puts this fix at $0 to $120.

How to test it. Pull out the lower rack. Twist the filter counterclockwise and lift it out. Whirlpool says to rinse it under warm water with a soft brush and then shine a flashlight into the sump below for toothpicks, seeds and broken glass. Put the filter back and turn it until it locks. Run a short cycle.

DIY or pro. DIY. Our step by step page on how to clean a dishwasher filter and spray arms walks through it. Whirlpool also says a steady hum with no water moving can point to a jammed pump impeller, and grinding can mean hard debris such as glass is in the pump area. If you see that, the next clean out is a bit deeper.

What it is. The drain hose runs from the pump to the sink drain or disposal. LG says heavy items stored under the sink can crush or kink it. Our cost box lists $0 to $180 for a hose that is kinked or plugged.

How to test it. Open the cabinet under the sink and follow the hose. Whirlpool says to check that it is not kinked, crushed or sagging, and to confirm a high loop is secured to the underside of the counter. LG also says the end of the hose must be 12 to 40 inches above the floor and the hose should be no longer than 12 feet.

The high loop. Without an air gap, the hose has to rise in a loop up under the counter before it drops to the drain. The loop keeps dirty sink water from running back into the tub. GE Appliances says to measure the height from the floor to the highest point of the hose and match the install instructions. A hose that sags low behind the machine is a classic cause of water left in the tub.

DIY or pro. DIY for straightening a kink or replacing a clamp. If the hose is old, GE says new dishwashers ship with a white corrugated hose and reusing an old, worn hose can promote kinking or a blockage. See our full DIY guide to fixing a dishwasher that is not draining for the hose steps.

What it is. A new disposal has a solid plug inside its dishwasher inlet. It keeps sink water from spilling out of the port if you do not have a dishwasher. If nobody punches it out, the dishwasher has nowhere to send its water. Whirlpool’s new install page says a retained plug blocks drainage completely, and Frigidaire and LG both list it as a cause. Our cost box puts the fix at $0 to $120.

How to test it. This one needs the disposal unplugged or its breaker off. Put a towel and a pan under the sink. Loosen the clamp and pull the dishwasher hose off the disposal inlet. Look into the port with a flashlight. If you see a solid disc, tap it out with a screwdriver and a hammer, then fish the disc out of the disposal body so it does not jam the blades.

DIY or pro. DIY. If you are not sure the disposal is truly off, call a pro.

What it is. An air gap is the small chrome or plastic cylinder on the sink deck near the faucet. Not every kitchen has one, and some local codes require it while others allow a high loop instead. When it fills with gunk, water cannot leave. Our cost box lists $0 to $120.

How to test it. Twist off the cap and look down. LG says to turn the dishwasher off, remove the cover and clear debris with a toothpick or a brush. GE Appliances says the same and adds that clearing it lets water flow better as the dishwasher drains. If water spills out of the air gap during a drain cycle, Whirlpool says the blockage is downstream in the hose or the sink plumbing, so move to the hose and disposal.

DIY or pro. DIY.

What it is. The drain pump pushes water out through the hose. When the path is clear and the tub still holds water, the pump is the next suspect. Our cost box puts a failed pump at $150 to $300 for a pro repair.

How to test it. Listen at the end of the cycle. Whirlpool says a hum with no water movement points to a jammed impeller, and no pump sound at all points to an electrical or control issue such as a door switch, wiring or the control board. A jammed impeller from glass or a bone is a cheap fix.

DIY or pro. This is the point where most people should call. Pump work means pulling the machine out and working near 120 volt wiring. See our page on dishwasher pump and motor repair cost for the full range. If your display shows a drain code such as OE on an LG or i20 on a Frigidaire, that code means the same thing, the machine could not empty itself.

Independent shops here usually charge a service call of $75 to $150, and most apply it toward the repair. The cost box above shows the full range for this job, $100 to $300 with parts at $0 to $90 and labor at $100 to $220. The chart below shows the high end of each cause. Four of the five can cost you nothing if you do them yourself.

Hard water. The City of Phoenix reports total hardness of 172 to 302 ppm, about 10 to 17.6 grains per gallon, in its 2025 water quality report. The USGS calls anything over 180 mg/L very hard. The same Phoenix report lists total dissolved solids at 464 to 716 ppm. Phoenix says hardness is not regulated under drinking water health standards, and that it can build up on plumbing fixtures. See our hard water explainer.

None of the manufacturer pages we read say scale is a leading cause of drain trouble, so we will not claim it is. What we can say is that mineral film on filter mesh and in a sump is something to look for while the filter is out. If the mesh looks crusty, soak it in warm water with white vinegar and brush it. LG suggests running a cleaning cycle with a cup of vinegar or dishwasher cleaner in the empty tub for slow drains.

New installs and remodels. Whirlpool’s new install page says most post install drain problems trace back to a kinked or misrouted hose, a missing or low drain loop, or a plug that was never removed. If your drain trouble started the week a disposal or dishwasher went in, start there.

Garages and heat. We did not find a source tying outdoor heat to drain failures, so we leave it out. Heat matters for other dishwasher jobs, and our page on dishwasher repair in Arizona covers those.

Call if you have cleaned the filter, cleared the hose and air gap, confirmed the plug is out, and the tub still holds water. Also call if the breaker trips, you smell burning, or the dishwasher hums or grinds with no water moving. Whirlpool says to stop and call a technician if you see damaged wiring or the breaker trips repeatedly.

Tell the dispatcher five things.

• The brand, model number and age of the machine.
• Whether it drains into a disposal, an air gap or a high loop.
• What you already tried, such as the filter, the hose and the air gap.
• Any display code, such as OE or i20.
• Whether a disposal or dishwasher was installed recently.

You can browse local shops on our Phoenix appliance repair page, or call us at (520) 412-6871.

For a drain problem, repair almost always wins. The cost box says repair, and usually just cleaning. A $100 to $300 fix on a working machine beats a new one.

Age matters if it is the pump. InterNACHI’s life expectancy chart lists a dishwasher at 9 years and a food waste disposal at 12 years. If your dishwasher is past 9 and the pump or board has failed at the top of our $150 to $300 range, put that money toward a new one. If it is under 9, repair it.