Dishwasher Not Draining? Fix It Tonight in 15 Minutes
- About 15 minutes
- 8 parts and tools
Standing water in the bottom of your dishwasher looks worse than it usually is. Most of the time the cause is a clogged filter, a kinked drain hose, or a blocked connection at the garbage disposal, and all three are fixable with basic household tools. Set aside about 15 minutes for the checks in this guide, plus time for one short test cycle. You will need towels, a cup for bailing, a flashlight, and possibly a screwdriver. You do not need to pull the dishwasher out of the cabinet for any of the steps below.
What's probably wrong
Work through these causes in order, because they are listed from most likely to least likely.
A clogged filter is the number one cause. Food, grease, and bits of paper collect in the filter at the bottom of the tub. When the filter is blocked, water cannot reach the drain pump, so it sits in the bottom after the cycle ends. This is especially common if you have not cleaned the filter in months, or if someone scraped plates poorly before loading.
A kinked or blocked drain hose is the next most likely cause. The drain hose runs from the dishwasher to the garbage disposal or to a drain connection under the sink. If the hose got pinched when something was pushed back under the sink, or if it sags low and traps food, water backs up into the tub. A hose that runs flat along the cabinet floor instead of looping up high under the sink can also cause slow draining.
A garbage disposal problem is a close third, and only applies if your dishwasher drains through a disposal. If the disposal is full of food, the dishwasher cannot push water through it. If the disposal is brand new, there is another classic cause. New disposals ship with a small plastic knockout plug sealing the dishwasher inlet. If the installer never knocked that plug out, the dishwasher has never been able to drain properly, and the problem shows up on the very first run.
A clogged air gap is less common but easy to check. Some kitchens have a small chrome cylinder on the sink or countertop next to the faucet. That is the air gap. It prevents dirty water from flowing back into the dishwasher. When it clogs with food, water may spit out of it during the drain cycle, or the dishwasher may drain slowly.
A failing drain pump is the least likely cause for a machine that was working fine yesterday. The pump can get jammed by a piece of glass, a bone fragment, or a twist tie. The pump motor itself can also wear out, but that usually gives warning first, such as louder draining noises over several weeks. If the pump runs and hums but moves no water after you have cleared the filter and hose, the pump is the suspect.
Fix it tonight
Start with safety. Switch off the breaker that serves the dishwasher, or unplug it if the plug is reachable under the sink. If you can reach the hot water shutoff valve under the sink, turn that off too. Lay towels on the floor in front of the dishwasher, because bailing always splashes a little.
First, bail out the standing water. Use a cup or a small container to scoop water from the bottom of the tub into the sink. Sponge out the last bit with a towel. You need the bottom clear so you can see the filter and the drain area.
Second, remove the bottom rack and take out the filter. The filter is usually a round or cylindrical part in the floor of the tub, sometimes under a flat mesh cover. It normally twists counterclockwise to unlock. Lift it out, along with any mesh screen that comes with it. Rinse everything under hot running water in the sink. Use an old toothbrush to scrub the mesh. If grease is caked on, soak the filter in hot soapy water for a few minutes, then scrub again. While the filter is out, shine a flashlight into the sump area where it sat. Look for glass, bones, or food chunks. Pick debris out with pliers or tongs, never with your bare fingers, because broken glass hides in dishwasher sumps. Put the clean filter back and twist it until it locks.
Third, check the drain hose under the sink. Open the cabinet and find the hose that comes from the dishwasher. Follow it from the dishwasher connection to the disposal or drain fitting. Straighten any sharp kinks. The hose should loop up high under the sink before it goes down to its connection. That high loop is deliberate, so do not reroute it flat. If the hose is crushed by a trash bin or a cleaning bottle, move the item and give the hose room.
Fourth, if you have a garbage disposal, run it. Turn on cold water and run the disposal for about 30 seconds to clear any food sitting in it. Then run the dishwasher drain again later and see if the water clears. If the disposal is new and the dishwasher has never drained correctly, the knockout plug is a strong suspect. To check it, you would disconnect the dishwasher hose from the disposal and look inside the inlet. If a solid plastic disc blocks the opening, it needs to be knocked out with a screwdriver and a few light hammer taps, with the disposal switched off at the breaker. If that sentence makes you nervous, skip it and call a pro. It is a small job, but it is fiddly work under a sink.
Fifth, check the air gap if you have one. Unscrew the chrome cap on top of the air gap and lift out the inner cap. Clear any food debris you find, rinse the parts, and put them back. If water was spitting from the air gap during the drain cycle, this often solves it on its own.
Sixth, restore power and run a test. Switch the breaker back on and start a short cycle, or use the cancel and drain function if your model has one. Watch the bottom of the tub. You should hear the drain pump run and see the water level drop within a minute or two. Let the cycle finish, then open the door and check. A tablespoon or two of water left near the drain is normal on many models. A visible pool is not, and means you should repeat the filter and hose checks before moving on to the pro section below.
One more tip for tonight. Do not run a full wash cycle with dirty dishes while the drain problem is unresolved. A full cycle adds more water to a tub that cannot empty, and it can overflow onto the floor. Run drain only until the problem is fixed.
Parts and tools
When to call a pro
Stop and call an appliance technician if the drain pump hums or runs but moves no water after you have cleaned the filter, straightened the hose, and cleared the disposal. That points to a pump or internal blockage that needs the machine pulled out and opened up. Call a pro if water is leaking from underneath the dishwasher or from the motor area, because that is not a drain clog anymore. Call a pro if the breaker trips when the dishwasher runs, if you smell burning, or if the control panel is dead after you restore power. Call a pro if the dishwasher is hardwired and you are not comfortable working around the breaker, or if the knockout plug job under the sink feels beyond you. Do not keep running drain cycles on a machine that is leaking or tripping the breaker.
What a pro typically costs
These are broad typical ranges, not quotes. Your area and your machine will change the number. A service visit to diagnose a dishwasher drain problem typically costs 150 dollars to 400 dollars, including the first hour of labor. Replacing a drain pump typically costs 250 dollars to 500 dollars in total, parts and labor included. Replacing a drain hose typically costs 150 dollars to 300 dollars installed. If the technician finds that the machine itself is failing in several ways at once, ask for the repair total in writing before approving it, and compare that number to the price of a new machine. A repair that costs more than half the price of a comparable new dishwasher is usually not worth doing.
FAQ
Why is there a little water left after every cycle?
A small amount of water near the drain is normal on many models. It keeps the pump seal wet so it does not dry out and crack. What is not normal is a visible pool covering the bottom of the tub, or water deep enough to touch the bottom rack.
Can I just run the dishwasher again and hope it drains?
No. Running a full cycle on a machine that cannot drain adds more water to the tub and risks an overflow. Run drain only, or cancel and drain, until the standing water clears and stays cleared through a full test cycle.
My dishwasher is new and has never drained right. Is it broken?
Probably not. On a new installation, the most common cause is the knockout plug in a new garbage disposal that was never removed. It is a five minute fix for a technician, and it is worth mentioning by name when you call, because it tells them exactly where to look.
How often should I clean the filter?
Once a month is a good habit for a household that runs the dishwasher daily. If you rinse dishes well before loading, every six weeks is fine. A clean filter drains faster, cleans better, and is the single easiest way to prevent the problem in this article from coming back.