Why Is My Dishwasher Not Draining? Causes and Fixes
Why a dishwasher leaves standing water, how to clean the filter and check the drain hose safely and when to call for dishwasher repair in Abilene, TX.
Standing water in the bottom of a dishwasher after a cycle is unpleasant, but it is one of the more fixable appliance problems. The water has a route out: the sump at the bottom, the drain pump, a hose and then either a garbage disposal or a drain line under the sink. A clog or failure anywhere along that route leaves water in the tub. This guide takes you through the checks in a sensible order.
Start with the sink
Dishwashers usually drain into the kitchen sink plumbing. Run the sink faucet and see if the sink drains quickly. If the sink is slow, or if you use a garbage disposal, run the disposal and clear any blockage first. A backed-up sink can send dirty water back into the dishwasher.
Clean the filter and sump
Almost every dishwasher has a filter in the bottom of the tub. Food and debris collect there and can block drainage. To clean it:
- Turn off power to the dishwasher at the breaker or unplug it if you can reach the cord.
- Remove the lower rack.
- Twist or lift out the filter and the cylinder around it, according to your model.
- Rinse the filter under the tap and scrub it gently with a soft brush.
- Look into the sump below for glass, bones, toothpicks or labels and remove them by hand, carefully.
- Replace the filter and check that it locks in place.
Cleaning the filter monthly prevents most drain problems.
Check the drain hose and air gap
The drain hose runs from the dishwasher to the sink drain or disposal. It should loop up high under the counter, then run to the drain. Look for kinks or crushing where the hose passes through the cabinet. If your kitchen has an air gap, a small fixture on the sink or counter, clean it out, since food can clog it.
The garbage disposal knockout plug
When a new garbage disposal is installed, the dishwasher inlet on the disposal is capped with a knockout plug. If the installer did not remove the plug, the dishwasher cannot drain through the disposal. This is a common cause for dishwashers that never drain properly after a new disposal or a new dishwasher installation.
The check valve and drain pump
Some dishwashers have a check valve that stops water from flowing back in from the drain. If it sticks, water can stay in the tub. If the filter, hose and disposal are all clear and water still stays, the drain pump may have failed. Signs include a humming noise with no water moving, no sound at all during the drain portion of the cycle, or a grinding sound from a jammed impeller. A pump is a wearing part and is usually a straightforward replacement.
Control problems
If the pump tests fine but never runs, the problem may be in the wiring or the control board. This is a job for a technician because replacing a control board without a proper test is costly.
What a technician will check
A technician will confirm the sink and disposal are draining, inspect the filter and sump, trace the drain hose and air gap, and test the check valve and drain pump. If the pump runs but water does not move, a hidden clog or a jammed impeller is likely. If the pump does not run, the technician tests power to the pump and the control signal to decide whether the pump, wiring or board is at fault.
What not to do
- Do not pour chemical drain cleaner into the dishwasher. It can damage the parts and is dangerous when someone opens the door.
- Do not run cycle after cycle hoping the water will clear.
- Do not stick your hand into the sump with the power on.
Keep it from coming back
Scrape plates, but you do not need to rinse them completely. Clean the filter once a month. Run hot water at the kitchen tap before starting a cycle. Use a dishwasher cleaner every couple of months, especially if you have hard water, which is common in West Texas and leaves scale that can narrow passages.
When to call for repair
Call if the water remains after you have cleaned the filter and checked the hose and disposal plug, if you hear humming or grinding, if the dishwasher leaks or if the same problem keeps returning. Have the brand, model number and any error code ready. Dishwashers commonly last around 9 to 12 years, and a pump or valve is usually worth replacing on a newer one.
See our dishwasher repair service in Abilene for details. Same-day and 24-hour emergency service are available; call (325) 876-4452.