Dishwasher not draining: causes, checks, and what each fix costs
Quick answer
A dishwasher not draining almost always comes down to one of four things: a clogged filter, a kinked or blocked drain hose, a faulty drain pump, or a garbage disposal that's either clogged or still has its knockout plug in place. Start with the filter — it's the most common culprit and takes five minutes to clean. If the filter is clear, check the drain hose for kinks and the disposal connection for blockages. A humming sound during the drain cycle points to the pump. Most of these are straightforward DIY fixes; a failed pump or control board is a pro job and may tip the scale toward replacement on an older machine.
Common causes
- Clogged or dirty filter/filter assembly (most common — food debris accumulates and blocks water flow)
- Blocked or kinked drain hose (hose pinched behind the machine or clogged with grease)
- Garbage disposal clogged or knockout plug not removed (especially after a new disposal install)
- Failed or seized drain pump (motor hums but doesn't move water)
- Blocked air gap on the sink (if installed — cap fills with debris and backs up the drain line)
- Faulty door latch or control board preventing the drain cycle from starting
What to check first
- Pull out the bottom rack and remove the filter assembly — twist it out, rinse under warm water, and scrub with a soft brush. Reinstall and run a rinse cycle.
- Look under and behind the dishwasher for the drain hose — confirm it has a high loop or air gap, isn't kinked, and isn't clogged where it connects to the disposal or drain.
- If you have a garbage disposal, run it for 30 seconds to clear any standing food. If the disposal was recently installed, check that the drain inlet knockout plug was removed.
- Check the air gap (the chrome cap on your sink near the faucet, if present) — unscrew the cap and clear any debris inside.
- Listen during the drain cycle: a humming or buzzing with no water movement suggests the drain pump motor is trying but seized — likely needs replacement.
- Check the door latch and run diagnostics if your model supports it — some machines won't start the drain cycle if the control board logs a door or sensor fault.
When it's urgent
">If you notice a burning smell during the drain cycle or the dishwasher trips the kitchen circuit, stop running it and unplug it or switch off the breaker. A seized pump motor can overheat. Have a licensed appliance technician inspect it before running another cycle.
DIY vs. call a pro
You can likely DIY
- Cleaning the filter assembly
- Checking and clearing the drain hose for kinks or soft clogs
- Clearing the garbage disposal and checking the knockout plug
- Cleaning the air gap on the sink
- Running a cleaning cycle with a dishwasher cleaner tablet to break up grease buildup
Call a pro for
- Drain pump motor replacement (requires pulling the machine and disassembly)
- Control board diagnosis and replacement
- Drain hose replacement if it runs inside the cabinet wall or requires moving the appliance
- Any work involving the electrical supply or hardwired connections
Estimated cost range
How HouseCue helps
HouseCue is a private, homeowner-first app that turns this from a one-time worry into a tracked plan. Snap a photo for an AI diagnosis, upload your inspection report to auto-build a handbook, and get seasonal reminders for your roof, HVAC, water heater, plumbing, and electrical — so nothing slips. Connecting with a pro is always optional and only when you choose.
See a free diagnosis — no signupFrequently asked questions
Why does my dishwasher have standing water at the bottom after the cycle?
A small amount of water in the very bottom of the tub (below the filter) is normal on many models — manufacturers design it that way to keep the door gasket from drying out. But if there's an inch or more of cloudy water sitting above the filter, that's a drainage failure. Start with the filter and drain hose checks above.
My dishwasher stopped draining right after I installed a new garbage disposal. What happened?
New garbage disposals ship with a knockout plug inside the dishwasher drain inlet. If it isn't removed before you connect the drain hose, water has nowhere to go. It's one of the most common install oversights. Disconnect the drain hose from the disposal, use a screwdriver and hammer to knock the plug into the disposal cavity, then fish it out before reconnecting.
Is it worth repairing a dishwasher that won't drain, or should I just replace it?
Use the rough rule of thumb: if the repair cost is more than half the price of a comparable new machine, and the dishwasher is over 8–10 years old, replacement usually makes more financial sense. Filter cleaning and hose fixes are almost always worth doing. A drain pump on a 5-year-old machine is typically worth fixing. A control board on a 12-year-old machine is usually not.
Can I run my dishwasher if it's not draining fully?
Not advisable. Standing water is a breeding ground for bacteria and mold, and repeatedly running the machine without proper drainage can overheat the pump motor and damage the tub lining. Fix the drainage issue first — the checks above take 15–20 minutes and solve most cases.
What does it mean if the dishwasher drains partially but leaves a little water?
Partial drainage usually points to a partial clog — either in the filter, the drain hose, or at the disposal connection. The pump is working, just not clearing fully. Clean the filter thoroughly, check the hose for a soft grease clog near the connection points, and run the disposal before starting a cycle.
Related guides
HouseCue guides are general educational information, not professional inspection, engineering, or contracting advice. Costs vary by market. For safety issues — gas, electrical, structural, or major water — contact a qualified professional.