Why Is My Dishwasher Not Draining? Causes and Fixes
1. Clogged or dirty filter
The filter is the first place to check. Modern dishwashers use a manual filter (usually a cylindrical mesh assembly under the lower spray arm) that collects food debris. A heavily clogged filter blocks the drain path entirely.
Fix: Twist and lift out the filter assembly. Rinse under warm running water, scrubbing with a soft brush. Reinstall firmly — a loose filter can also cause poor drainage. Clean it at least once a month.
2. Blocked drain pump or sump area
Small items — broken glass, citrus seeds, cherry pits, toothpicks — can pass through the filter and jam the drain pump impeller. You'll often hear the pump hum but water won't move.
Fix: Remove the lower spray arm and filter, then look down into the sump area with a flashlight. Use needle-nose pliers to clear any obstruction. If the impeller spins freely but water still won't drain, the pump motor itself may have failed and needs replacement.
See our guide on how to replace a dishwasher drain pump for full steps.
3. Kinked or clogged drain hose
The drain hose runs from the pump to either your garbage disposal or the sink drain. A sharp bend in the hose creates a siphon trap that holds water back. Grease buildup inside the hose has the same effect.
Fix: Pull the dishwasher out slightly and inspect the hose run behind it. Straighten any kinks. The hose should loop up high (ideally secured to the underside of the counter) before dropping to the drain connection — this high-loop prevents backflow. If the hose is clogged, disconnect it and flush with warm water.
4. Garbage disposal knockout not removed
If you recently replaced your garbage disposal and now the dishwasher won't drain, the knockout plug inside the disposal's dishwasher inlet may still be in place. This is a very common oversight.
Fix: Disconnect the drain hose from the disposal. Insert a screwdriver into the inlet port and tap through the plastic knockout plug. Retrieve the plug fragments from inside the disposal before reconnecting.
5. Air gap or drain connection blocked
Some installations include an air gap (a chrome cylinder on the sink deck) to prevent drain backflow. The air gap itself can become clogged with debris, which backs up and prevents draining.
Fix: Unscrew the air gap cap, pull out the inner cap, and clean both with a brush. Check the short hose between the air gap and the disposal for grease buildup.
6. Error codes that signal a drain problem
Most brands surface a specific error code when a drain issue is detected. Common ones include:
- E24 (Bosch) — drain path restriction
- E25 (Bosch) — drain pump obstruction
- E22 (Bosch) — filter or drain blockage
- OE / 5E (Samsung, LG) — drain timeout
Browse all dishwasher error code guides to find your specific code and brand.
When to call a technician
Stop DIY and call a licensed appliance tech if:
- The drain pump hums but the impeller is not jammed — the motor has likely failed
- Water leaks onto the floor when the drain cycle runs
- The control board is showing multiple unrelated fault codes
- The dishwasher is under warranty — self-repair may void it
Frequently asked questions
Can I run the dishwasher with standing water at the bottom?
Run one short cycle to see if the water drains on its own. If it doesn't, stop using the dishwasher until the root cause is fixed — continued use can overheat the pump motor.
How often should I clean the dishwasher filter?
Once a month for most households, or every two weeks if you run the dishwasher daily or skip pre-rinsing dishes.
Why is my new dishwasher not draining?
On a brand-new install, the most likely cause is a garbage disposal knockout plug that was not removed. It's a 5-minute fix — see Section 4 above.
Does a dishwasher drain into the sink drain?
Yes. The drain hose connects either directly to the drain tailpiece under the sink, or to a port on the garbage disposal. Blockages in either location will prevent draining.