Dishwasher
Dishwasher not draining: what to check and what it means
Water sitting in the bottom of a dishwasher is one of the calls we see most, and a lot of them start with a filter nobody knew was there. Here is what to check yourself, what the real causes look like, and when it needs a technician.
A little water is normal, a pool is not
Most dishwashers keep a small amount of water in the sump, the low well under the filter, to keep the seals wet. That is normal. What is not normal is water above the filter, covering the tub floor, after a cycle has finished. A sour or rotten smell usually comes with it, because that water sits between cycles.
Also note whether the cycle ended normally or stopped with an error code or blinking lights. Many dishwashers stop mid-cycle and flash a code when they cannot drain. Write it down exactly.
The process
What you can safely check first
- Cut the power
Turn off the dishwasher at its breaker, or unplug it if it plugs in under the sink. Do this before you reach into the tub or touch the filter.
- Bail out the water
Pull the lower rack and scoop the water out with a cup, then soak up the rest with a towel or sponge. The water may be hot if a cycle just ran.
- Clean the filter
In the tub floor, under the lower spray arm, there is a cylindrical filter that twists out. Remove it, rinse it under the tap with a soft brush, and check the opening under it for glass, bones, seeds or labels. Twist it back until it locks.
- Check the garbage disposal
If the dishwasher drains into a disposal, run the disposal with water for a while to clear it. If the disposal was just installed, the knockout plug inside the dishwasher inlet may never have been removed; that is a common cause on a new install.
- Look at the drain hose under the sink
Make sure the hose is not kinked or crushed behind the storage under the sink and that it loops up high before connecting to the sink drain or disposal. If you have an air gap on the countertop, pull the cap and clear any debris.
- Run a short test
Restore power and run a rinse or short cycle with an empty tub. Listen at the end for the drain pump, a steady whirring, and check whether the water clears.
The real causes, from most to least common
Clogged filter. By far the cause we find most. Food that was not scraped off the plates builds up on and under the filter until water cannot get through to the pump. What it looks like: slow draining that gets worse over weeks, a smell, and a gritty layer in the tub. Cleaning it fixes it. Once a month keeps it from coming back.
Clogged drain hose or sink connection. Food sludge collects in the drain hose and where it meets the disposal or the sink drain. What it looks like: the drain pump runs normally but water drains slowly or not at all, and the kitchen sink may gurgle or back up while the dishwasher drains.
Blocked or failed drain pump. The drain pump sits under the sump. Glass, a pit, or a piece of bone can jam its impeller, and the motor can fail. What it looks like: a hum or buzz with no water moving, a grinding noise, or silence where you would expect the drain. A jammed pump sometimes frees up once the debris is out; a burned-out motor needs to be replaced.
Check valve or drain flapper stuck. The check valve keeps drained water from flowing back into the tub. When it sticks closed, nothing gets out. When it sticks open, dirty water flows back in from the hose or the sink. What it looks like: water returning to the tub after it drained, or dirty water appearing even though the dishwasher was not running.
Kinked hose from an install or a cabinet change. Very common right after a new dishwasher goes in or after things under the sink get rearranged. What it looks like: the problem started right after the work.
Control board or wiring. The least common. A failed relay on the control board means the drain pump never gets power, often with an error code. What it looks like: no pump sound at all with a clean filter and a clear hose.
When to call a technician
Call us if:
- The filter is clean, the disposal is clear, the hose is straight, and it still holds water.
- The drain pump hums, grinds, or makes no sound when it should drain.
- Water keeps coming back into the tub after it drains.
- There is water on the floor or under the door, or the cabinet floor under the sink is wet.
- The same error code returns after you cleaned the filter.
- It is under a manufacturer, extended or home warranty. File with the plan first; our warranty repair page explains how we handle those dispatches.
If water is leaking onto the floor, turn the dishwasher off at the breaker and close the water valve under the sink, then dry everything. If you smell burning, see smoke or sparks, or get a shock from the door or the tub, stop using it and leave the breaker off.
Our technicians have over 15 years of repair experience, and we diagnose before we quote. See our dishwasher repair service for more, or request a visit. We cover homes in Stafford, Fredericksburg and Locust Grove.
Questions
Dishwasher draining questions
Is it normal to have water in the bottom of my dishwasher?
A small amount in the sump under the filter is normal. Water covering the tub floor after a finished cycle is not; that means it is not draining.
How do I clean a dishwasher filter?
Turn off the power, pull out the lower rack, twist the round filter in the tub floor counterclockwise and lift it out. Rinse it under warm water with a soft brush, clear any debris from the opening, and twist it back until it locks. Once a month is a good habit.
Can a garbage disposal stop a dishwasher from draining?
Yes. A full or clogged disposal blocks the dishwasher drain. On a new disposal, the knockout plug for the dishwasher inlet may still be in place. Run the disposal first and check that before anything else.
Should I pour drain cleaner into my dishwasher?
No. Chemical drain cleaners can damage the pump, seals and hoses, and leave the next person who works on it exposed to caustic water. Clean the filter and check the hose instead, and call us if that does not clear it.
Water still sitting in the tub?
Tell us the brand, any error code, and what you have already checked. We confirm a day and arrival window with you before anything is locked in.