Dishwasher Not Draining? Check These 8 Things in Order
Quick answer
Most dishwashers that won’t drain have one of three problems: a clogged filter or sump at the bottom of the tub, a kinked or crushed drain hose under the sink, or a blockage at the garbage disposal (including a knockout plug that was never removed after installation). Check those first. If the water is still there after you’ve cleared them, the drain pump may be blocked or faulty, and that usually means a service call.
Safety first
- Turn off the power at the breaker (or unplug the dishwasher) before you reach into the bottom of the tub.
- The standing water may be hot. Let it cool first.
- Bosch warns that debris in the pump area can be sharp, such as broken glass, and LG warns that metal filters can have sharp edges. Wear gloves.
- Never put your hand into a garbage disposal. GE specifically warns against it.
- Do not pour chemical drain cleaner into the dishwasher. GE advises against it.
First: is the water actually a problem?
A little water at the bottom can be normal. According to GE Appliances, on its models without an Ultra Fine filter, 1 to 2 cups of clean water covering the bottom of the tub is normal. On models with an Ultra Fine filter, water in the filter area (the sump) is normal, but it should not cover the bottom of the tub. Check your manual for your model. If there are a few inches of dirty water, or the dishwasher shows a drain error, keep going.
Also make sure the cycle actually finished. If the dishwasher stopped mid-cycle (a power blip or the door was opened), cancel the cycle and start it again so the dishwasher runs its drain step. On Frigidaire models, for example, you press and hold Cancel for 5 to 10 seconds to clear the cycle, then start a new one.
How water leaves a dishwasher
Water passes through the filter into the sump, the drain pump pushes it through the drain hose, the hose rises to a high loop or air gap under the counter, and it empties into the garbage disposal or sink drain. The checks below follow that path, starting with the easiest.
1. Clear the bottom of the tub
Pull out the lower rack and look at the sump area at the back or center of the tub floor. GE notes that paper, labels, or large food pieces (noodles, lettuce, bones) can cover or block the sump. Remove anything you find.
2. Clean the filter
A clogged filter is the most common cause, according to Bosch. Most current dishwashers have a filter you can twist out by hand:
| Brand (examples) | What the manufacturer says |
|---|---|
| LG | Turn the filter counterclockwise to remove it, clean it under running water with a soft brush, and turn it clockwise until it clicks. |
| Bosch | Remove the filter and clean it with soap and a soft brush under running water. |
| GE | On models with Fine and Ultra Fine filters, remove and check both filters at the bottom of the tub. |
| Frigidaire | Remove the glass trap and filter and rinse them with warm water. |
Filter designs vary by model. Your owner's manual shows exactly how yours comes out. Source: Manufacturer support pages listed below
Put the filter back the way it came out and make sure it locks. Then run a short cycle to see if it drains.
3. Run the garbage disposal
If your dishwasher drains into a garbage disposal, a clogged disposal will stop it from draining. Whirlpool’s advice is to clear the disposal by running it, then start a drain cycle on the dishwasher. GE recommends running the disposal before every dishwasher cycle to clear food from the drain system.
4. New dishwasher or new disposal? Check the knockout plug
New garbage disposals come with a plug sealing the dishwasher inlet. If it isn’t removed when the dishwasher is connected, the dishwasher can’t drain at all. Whirlpool calls this a common misdiagnosis, and GE, LG, and Frigidaire all list it. The disposal’s installation instructions explain how to remove the plug. If you are not comfortable doing it, this is a job for the installer or a plumber.
5. Check the drain hose under the sink
Open the cabinet under the sink and follow the drain hose (usually white or gray and ribbed):
- Kinks or crushing. LG notes that heavy items stored under the sink can crush or kink the hose. Straighten it and move whatever was pressing on it.
- A high loop or an air gap. The hose must either rise in a high loop secured under the counter or connect to an air gap, depending on local code. Whirlpool explains that a hose that sits too low can let water flow back into the tub.
- The right hose and length. GE says to use the corrugated drain hose that came with a new dishwasher, because re-using an old, worn hose can lead to kinks and blockages. LG’s installation requirements, for example, say the hose must be no more than 12 feet long and its end must be 12 to 40 inches above the floor. Your model’s installation instructions give its exact limits.
6. Clean the air gap
If there is a small chrome or plastic cap on top of your sink next to the faucet, that is the air gap. GE and LG both recommend removing the cap and clearing out any debris. LG says to turn the dishwasher off first.
7. Check the detergent
GE notes that the wrong type of detergent, or too much of it, can make so many suds that the dishwasher can’t drain properly. Hand dish soap in a dishwasher is a common cause. Use only automatic-dishwasher detergent in the amount the manual recommends.
8. Check the drain pump area (only if your manual allows it)
Some dishwashers let you open the pump cover to remove debris. Bosch, for example, says that after removing the filter you can take off the pump cover following the owner’s manual, remove any debris and standing water with a sponge, and then reinstall the cover and filter. Bosch notes that the debris can be sharp, so wear gloves, and only do this if your manual describes it. If your dishwasher has no user-removable pump cover, skip this step.
Also check that the kitchen sink itself drains. GE points out that a clogged sink drain will back up the dishwasher too.
Drain error codes
Many dishwashers show a code when they can’t drain. A few examples from manufacturer support pages:
- LG: OE means the dishwasher is not draining properly.
- Frigidaire: i20 means the unit did not drain properly.
- Bosch: E24 and E25 can mean the drain pump is blocked or its cover is loose. Bosch lists a kinked drain hose and a clogged air gap or hose as other causes of E24.
The checks above apply to all of them. Your manual or the manufacturer’s support site will list your model’s codes.
Call a pro if…
- The water is still there after you have cleaned the filter, checked the hose, the disposal, and the air gap. LG and GE both say a part may be faulty at this point and service is needed. A failed drain pump or a control problem is not a DIY fix on most models.
- Water is leaking onto the floor, you smell burning, or the breaker trips.
- You have a portable dishwasher that connects to the faucet (a unicouple). GE says those need service if they won’t drain.
- The dishwasher is under warranty. Opening the pump area yourself may affect it, so contact the manufacturer first.
How to keep it from happening again
- Scrape large food pieces off dishes before loading.
- Clean the filter regularly. Your manual gives the recommended interval.
- Run the garbage disposal before you start the dishwasher.
- Keep heavy items away from the drain hose under the sink.
