Dishwasher not draining? What to check first

Water left in the bottom after a cycle is sometimes a blockage, and sometimes normal (see the next section). These checks come from the manufacturers' own support pages. Work through them in a sensible order, easiest first, and stop when it drains.

Is this actually a problem? GE says that on models without an Ultra Fine filter, 1 to 2 cups of clean water covering the bottom of the tub is normal. On models with an Ultra Fine filter, water in the sump (the filter area) is normal, but it should not cover the bottom of the tub. If that is all you see, nothing is wrong. Source: GE Appliances, Dishwasher: Not Draining.

Before you start. Whirlpool says to turn off power to the dishwasher at the circuit breaker, not just the control panel, and to shut off the water at the under-sink valve. Whirlpool also says not to use drain-opening chemicals inside the dishwasher. GE says not to put your hands into a garbage disposer to check it. Sources: Whirlpool, Dishwasher Not Draining and the GE page above.

What to check, easiest first

Bail out the standing water with a cup, or a turkey baster for the sump, so you can see what you are doing.
Clean the filter. Bosch calls a clogged filter or pump "the most common reason for a dishwasher to stop draining". Remove the filter (your owner's manual shows how for your model), rinse it under running water and scrub gently with a soft brush. Whirlpool lists food particles, labels, seeds, toothpicks and glass as common culprits in the sump below it.
Check the drain hose. Make sure it is not kinked, crushed or sagging. Without an air gap, the hose must have a high drain loop secured under the counter; GE says the hose height must match the installation instructions.
Clear the air gap, if you have one. It is the small fitting on the sink or counter. GE: remove the cap and clean out any build-up of debris.
Look at the sink and disposal side. If the sink drain is clogged, the dishwasher cannot empty; GE says to run the disposer to clear the drain system (hands out of it). If a garbage disposal was recently installed or replaced, make sure the knockout plug in the disposal inlet was removed (Whirlpool and GE both list this).
Check the detergent. GE notes that the wrong type, or too much, can cause over-sudsing that stops the dishwasher draining.
Look at the pump. Bosch describes removing the pump cover (per your manual) and clearing debris with a sponge; some debris may be sharp, so take care. Keep the breaker off while you do this, and if you are not comfortable removing panels or accessing components, Whirlpool says to schedule service instead.

Then, per Whirlpool, run a short cycle and listen for the pump. Bosch's support page for the filter and pump steps: Dishwasher not draining.

When to call a pro. If it still will not drain after these checks, a jammed pump or a control problem is likely and it needs service. Whirlpool says to stop and contact a qualified technician if you smell burning, see damaged wiring, or the breaker trips repeatedly. Do not open electrical parts yourself. GE adds that a portable dishwasher connected to the sink with a unicouple that is not draining will need service.

The exact steps differ by brand and model, so follow your owner's manual. Not sure of your model? See how to find your model number and how to find the manual.

Whirlpool, GE and Bosch are trademarks of their respective owners. HomeGear isn't affiliated with or endorsed by them.

Common questions

Why is there water at the bottom of my dishwasher? A small amount can be normal (see above). If there is more, common causes are a clogged filter, a kinked drain hose or a blocked sink drain or air gap. Bosch calls a clogged filter or pump the most common reason a dishwasher stops draining.
Can I use drain cleaner in the dishwasher? No. Whirlpool warns that drain-opening chemicals can damage components and create safety hazards.
Why did it stop draining after a new disposal went in? Check that the knockout plug in the disposal inlet was removed.