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 blocked garbage disposal (including a knockout plug left in after installation). Check those first. If water still stands in the tub after that, 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.
- Wear gloves. Debris in the pump area can be sharp, such as broken glass (Bosch), and metal filters can have sharp edges (LG).
- Never put your hand into a garbage disposal. GE warns against it specifically.
- Skip chemical drain cleaner. GE advises against pouring it into the dishwasher.
First: is the water actually a problem?
Some water can be normal. On GE models without an Ultra Fine filter, 1 to 2 cups of clean water covering the tub floor is normal. On GE models with one, water belongs only in the filter area (the sump), not across the tub floor. A few inches of dirty water, or a drain error code, means keep going.
Also make sure the cycle finished. If it stopped partway (a power blip or an opened door), cancel it and start again so the drain step runs. On Frigidaire models, for example, hold Cancel for 5 to 10 seconds, then start a new cycle.
How water leaves a dishwasher
Water goes through the filter and sump, then the drain pump pushes it through the drain hose, up to a high loop or air gap, and into the disposal or sink drain. The checks below follow that path.
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. Paper, labels, and large food pieces (noodles, lettuce, bones) can block the sump, according to GE. Remove anything you find.
2. Clean the filter
Bosch names a clogged filter as the most common cause. Most current models have a filter that twists 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 and make sure it locks, then run a short cycle to test. For each brand’s filter location and cleaning schedule, see how to clean a dishwasher filter.
3. Run the garbage disposal
A clogged disposal will stop a dishwasher that drains into it. Whirlpool’s fix is to run the disposal, then start a drain cycle. GE suggests making it a habit: run the disposal before every dishwasher cycle. If the disposal only hums when you switch it on, see garbage disposal humming but not spinning.
4. New dishwasher or new disposal? Check the knockout plug
New garbage disposals come with a plug sealing the dishwasher inlet. If nobody removes it when the dishwasher is hooked up, the dishwasher can’t drain at all. Whirlpool calls this a common misdiagnosis, and GE, LG, and Frigidaire list it too. The disposal’s installation instructions show how to remove the plug, or the installer or a plumber can do it.
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. Heavy items stored under the sink can crush or kink the hose (LG). Straighten it and move whatever was on it.
- A high loop or an air gap. Depending on local code, the hose must rise in a high loop secured under the counter or connect to an air gap. A hose that sits too low can let water flow back into the tub, Whirlpool explains.
- The right hose and length. GE says to use the corrugated hose that came with a new dishwasher, because an old, worn hose can kink and clog. Limits vary by brand. LG, for example, caps the hose at 12 feet and puts its end 12 to 40 inches above the floor. Your installation instructions give your model’s numbers.
6. Clean the air gap
A small chrome or plastic cap on the sink next to the faucet is the air gap. GE and LG both say to remove the cap and clear out debris. Turn the dishwasher off first, as LG advises.
7. Check the detergent
The wrong type of detergent, or too much of it, can make so many suds that the dishwasher can’t drain properly (GE). Use only automatic-dishwasher detergent, never hand dish soap, in the amount your manual recommends. Dishwasher Not Cleaning Dishes Well has more on detergent.
8. Check the drain pump area (only if your manual allows it)
Some dishwashers have a pump cover you can open. Bosch, for example, says that with the filter out you can take off the pump cover as the owner’s manual shows, sponge out debris and standing water, and reinstall the cover and filter. Wear gloves, since the debris can be sharp. If your manual doesn’t describe a removable pump cover, skip this step.
Also check that the kitchen sink itself drains. A clogged sink drain will back up the dishwasher too (GE).
Drain error codes
Many dishwashers show a code when they can’t drain. Examples from the manufacturers:
- LG: OE means the dishwasher is not draining properly. (AE is a leak code; see LG Dishwasher AE or E1 Code.)
- Frigidaire: i20 means the unit did not drain properly.
- Bosch: E24 and E25 can mean a blocked drain pump or a loose pump cover. Bosch also lists a kinked drain hose and a clogged air gap or hose for E24. See Bosch Dishwasher E24 or E25 Error.
The checks above apply to all of them. Your manual lists your model’s codes.
Call a pro if…
- Water is still there after you’ve cleaned the filter and checked the hose, disposal, and air gap. LG and GE both say a part may be faulty at this point and service is needed. A failed drain pump or control problem is not a DIY fix on most models.
- Water leaks 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 on your manual’s schedule.
- Run the garbage disposal before you start the dishwasher.
- Keep heavy items away from the drain hose under the sink.
