Check and clean the dishwasher filter, then inspect the drain hose for kinks or clogs. If water still remains, test the garbage disposal and drain pump. Most fixes are simple and cost nothing.
A dishwasher that won't drain is frustrating. You open the door expecting clean dry dishes and find a pool of murky water. This problem is common but usually easy to fix. Our editorial team compared specifications, buyer feedback and key decision factors to bring you this troubleshooting guide. We cover the four main causes: a clogged filter, a blocked drain hose, garbage disposal issues, and a faulty pump. Follow the steps below to get your dishwasher draining again.
Why Your Dishwasher Is Not Draining
Dishwashers drain by pumping water through a hose into your kitchen sink's drain or garbage disposal. When something blocks that path, water stays in the tub. The most common culprits are:
- Clogged filter: Food particles and debris accumulate in the filter at the bottom of the dishwasher. If not cleaned regularly, they block water flow. Over time, a thick layer of grease and food residue can form, reducing drainage efficiency. For example, a filter clogged with rice or pasta can completely stop water from passing through.
- Blocked drain hose: The hose that carries water out can become kinked, pinched, or clogged with grease and food scraps. A kink often occurs when the dishwasher is pushed back under the counter, pinching the hose against the cabinet. Grease buildup is common in homes that wash oily pans without scraping them first.
- Garbage disposal issues: If your dishwasher drains into a garbage disposal, a clog in the disposal or a missing knock-out plug can prevent drainage. The knock-out plug is a plastic disc that must be removed when installing a new disposal. If it is still in place, water cannot flow into the disposal. Also, if the disposal is jammed or full of food waste, water will back up into the dishwasher.
- Faulty drain pump: The pump that pushes water out may fail due to a broken impeller, motor, or electrical issue. A pump can fail silently with no noise, or it may hum but not spin. Broken glass or a small bone can lodge in the impeller, stopping it from turning. Over time, the pump motor bearings can wear out, causing the pump to seize.
How to Fix a Dishwasher That Won't Drain
Before you call a repair person, try these step-by-step fixes. Always unplug the dishwasher or turn off the circuit breaker before reaching inside.
- Check and clean the filter. Remove the bottom rack and locate the filter assembly (usually a cylinder or flat screen). Twist and lift it out. Rinse it under hot water and scrub away debris with a soft brush. Pay special attention to the fine mesh screen where small particles get trapped. Reinstall it securely, ensuring it clicks into place. A loose filter can allow debris to bypass and clog the drain.
- Inspect the drain hose. Pull the dishwasher out from under the counter. Look at the hose connecting the dishwasher to the sink drain or disposal. Straighten any kinks. Disconnect the hose and check for clogs by running water through it. Use a long brush or pipe cleaner to remove blockages. For grease clogs, flush the hose with hot water and dish soap. If the hose is cracked or brittle, replace it with a new one of the same diameter.
- Clear the garbage disposal. If your dishwasher drains into a disposal, run the disposal to clear any food waste. Also check that the knock-out plug (a plastic disc) has been removed from the disposal's dishwasher inlet. If it's still there, use a hammer and screwdriver to break it out. Be careful not to damage the disposal housing. After removing the plug, run the disposal again to ensure water flows freely.
- Test the drain pump. Listen for a humming sound during the drain cycle. If you hear a hum but no water moves, the pump may be jammed. Remove the pump cover (consult your manual) and check for obstructions like a broken glass shard or bone. Spin the impeller manually to see if it's stuck. If the pump is silent, it may be electrically dead and need replacement. Use a multimeter to test for continuity across the pump terminals; if there is no continuity, the pump motor is burned out.
- Check the drain solenoid and float switch. Some dishwashers have a float switch that tells the control board when to drain. Make sure the float moves freely and the switch clicks. A stuck float can prevent draining. Also, inspect the drain solenoid (if equipped) for proper operation; it should click when the drain cycle starts. If the solenoid is defective, it may not open the drain valve.
When to Call a Professional
If you have tried all the steps above and water still remains, the issue may be a failed drain pump motor, a broken control board, or a wiring problem. These repairs require specialized tools and knowledge. Call a licensed appliance technician. Replacing a pump costs around $100 to $200 for parts plus labor. Check the current price of a replacement pump on Amazon if you plan to DIY.
When to Replace the Dishwasher
If your dishwasher is more than 10 years old and the pump or control board fails, replacement is often more cost-effective than repair. Newer models are more energy-efficient and have better cleaning performance. Compare prices on Amazon for the latest dishwashers. Signs it's time to replace: frequent breakdowns, rust inside the tub, or a drain problem that recurs after fixing. Also consider replacement if the cost of repair exceeds half the price of a new unit.
Preventing Future Drainage Problems
To avoid a repeat, clean the filter every month. Scrape large food scraps off plates before loading. Run the garbage disposal before starting the dishwasher. Once a year, check the drain hose for kinks and clean it with a vinegar and baking soda flush. These simple habits keep your dishwasher draining smoothly. Additionally, avoid putting starchy foods like oatmeal or pasta down the drain, as they can create stubborn clogs. Use a rinse aid to reduce grease buildup on dishes and in the drain system.
Understanding the Drain Cycle Sequence
Knowing how your dishwasher drains can help you diagnose problems. At the end of a cycle, the control board activates the drain pump. The pump pushes water through the drain hose and into the sink drain or garbage disposal. A check valve (often a rubber flap) prevents water from flowing back into the dishwasher. If the check valve is stuck open or clogged, water can return after draining. To test, remove the check valve and clean it. Also, some dishwashers have a high loop in the drain hose to prevent backflow; ensure the loop is at least 20 inches above the floor.