Start with the dishwasher filter
Most current dishwashers have a filter assembly at the bottom of the tub that you twist and lift out. Food, labels, glass and seeds collect in it and in the sump below, and a clogged filter is the most common reason water sits after a cycle. Take the lower rack out, remove the filter, rinse it under the tap with a soft brush and wipe out the sump. Put it back so it locks; a loose filter lets debris through to the pump.
Then follow the water out
From the sump, the drain pump sends water through a hose that rises in a high loop under the counter, then either through an air gap on the sink or counter or directly into the sink drain or the disposal. Each point can block.
- The sink. If the kitchen sink drains slowly or backs up when the dishwasher drains, the blockage is in the house drain, not in the machine.
- The disposal. Run the disposal before starting the dishwasher; food packed in it blocks the dishwasher inlet.
- The knockout plug. A disposal installed recently may still have the plug in its dishwasher inlet. The water has nowhere to go until it is knocked out.
- The air gap. If there is a small cap on the sink deck, pull it off and clean the chamber below. A clogged air gap often shows as water spilling from it into the sink.
- The hose. Check for kinks where the dishwasher was pushed into its opening, and make sure the hose loops up high under the counter before it drops to the drain.
The high loop and the air gap exist for the same reason: to keep dirty sink water from siphoning or backing up into the dishwasher. Where local plumbing code calls for an air gap, it has to stay in place.
When the drain pump is the problem
If the filter is clean and water still stays, listen at the end of the cycle. A drain pump that hums but moves no water may have a piece of glass or a bone jammed in the impeller; one that makes no sound may have failed or may not be getting power from the control. Some models also have a small check valve at the pump outlet that sticks. These are jobs for a technician on most machines, since the pump is reached from underneath or behind the tub.
Fixr lists pump repair at $100 to $250 and pump replacement at $150 to $400, both with labor. A drain hose replacement is $50 to $100.
What the fix usually costs
| Problem or part | Parts and labor |
|---|---|
| Will not drain | $50–$400 |
| Drain hose | $50–$100 |
| Filter | $50–$125 |
| Pump repair | $100–$250 |
| Pump replacement | $150–$400 |
| Bad smell | $50–$400 |
Fixr national dishwasher repair guide, updated January 31, 2025. Most technicians charge a $50 to $75 diagnostic fee and deduct it from the bill if they make the repair.
When some of the water drains and some stays
When only part of the water leaves, with an inch or so still on the tub floor, the blockage is usually partial: a filter that is half clogged, a hose that is pinched but not closed, an air gap slowly filling with grease. A pump that is weakening can also leave water behind. Go through the same checks in the same order; the difference is only how far along the blockage is.
What to tell the company
Say how much water is left, whether you hear the pump running at the end of the cycle, and whether the sink or the air gap overflows when the dishwasher drains. Mention a new disposal or new plumbing work if there was any. Give the model number from the label, and ask whether the $50 to $75 diagnostic fee counts toward the repair. The dishwasher repair page covers the other common faults.
Questions people ask next
Is a little water in the bottom normal?
A small amount around the sump, below the filter, is normal on many models; it keeps the seals from drying out. Water covering the tub floor or reaching the lower spray arm after a finished cycle is not.
My new disposal was just installed and now the dishwasher won't drain. Why?
The disposal's dishwasher inlet is closed with a knockout plug when it leaves the factory. If the installer did not knock it out before connecting the drain hose, the dishwasher has nowhere to send its water. Unplug the disposal, remove the hose and look into the inlet.
Can I bail out the water and keep using it?
You can bail and sponge it out to reach the filter, but running more cycles on a blocked drain only adds water, and a dishwasher that stops mid-cycle can leave detergent in the tub. Find the cause before the next load.
Sources
- How much does it cost to repair a dishwasher?, Fixr, updated January 31, 2025.
Reviewed October 1, 2026. Spotted an error? Write to admin@compareappliancerepair.com.