A little water in the bottom of a dishwasher sump after a cycle is normal on many models. An inch or more of murky water sitting over the filter is not. The good news is that most dishwasher drain problems are clogs, and many of them are reachable from the kitchen without moving the dishwasher at all.
Is it really a drain problem?
Check a few things first:
- •Did the cycle finish? If the dishwasher was interrupted, or the door was opened mid-cycle, it may not have gotten to the drain step. Close the door and run a short or rinse cycle to see if it drains.
- •Is the water small in volume and clear? A small amount of clean water around the sump or filter can be normal.
- •Is there a drain error on the display? LG dishwashers show OE. Bosch uses E24 and E25, which our Bosch dishwasher guide explains along with the pump cover you can check on those models. Other brands have their own codes; check your manual. Either way, the checks below are where to start.
Safety first
Turn off power to the dishwasher before reaching into the sump or working on the drain. Most dishwashers are either plugged in under the sink or hardwired with a switch or breaker. If you're working under the sink near the garbage disposal, switch off the disposal too.
Step 1: Clean the filter
Most modern dishwashers have a filter in the bottom of the tub that you twist out by hand. It catches food, glass shards, labels and fruit pits. A clogged filter stops water from reaching the drain pump.
- Scoop or sponge out the standing water.
- Twist out the filter, following the arrows or instructions in your manual.
- Rinse it under warm running water, scrubbing gently with a soft brush.
- Check the opening beneath it for anything lodged, like broken glass or a bone. Be careful with sharp objects.
- Reinstall the filter firmly — a loose filter lets debris through to the pump.
Step 2: Check the garbage disposal
Many dishwashers drain through the garbage disposal. If the disposal is full of food, the dishwasher can't push water through it. Run the disposal with cold water for a few seconds, then try a drain cycle.
If your disposal was just installed, there's a classic culprit: the knockout plug. New disposals have a plastic plug inside the dishwasher inlet that must be removed during installation. If nobody knocked it out, the dishwasher has nowhere to drain. It's a quick fix for whoever installed the disposal, but only if they know to check it.
Step 3: Check the air gap
Many LA kitchens have a small cylindrical cap on the sink or countertop next to the faucet. That's an air gap. It prevents dirty sink water from siphoning back into the dishwasher, and it's a common clog point.
Pull or twist off the cover, remove the inner cap, and clear out any food or gunk with a brush or small tool. If water sprays or leaks out of the air gap when the dishwasher drains, it's a strong sign of a clog downstream of it — in the hose to the disposal or the disposal itself.
Step 4: Look at the drain hose
Under the sink, follow the dishwasher's drain hose. It should rise up in a loop or connect to the air gap before going down to the disposal or drain. Look for:
- •Kinks, especially where the hose passes through the cabinet wall or behind stored items
- •A missing high loop. Without an air gap or high loop, dirty water can flow back into the dishwasher.
- •Blockages. If you're comfortable, disconnect the hose at the disposal or drain end (with a bucket and towels ready) and check that it's clear.
Step 5: Check the kitchen drain
If the sink itself drains slowly or backs up, the problem may be in the house plumbing, not the dishwasher. A dishwasher shares the drain with the sink, so a clog there affects both. A clogged kitchen drain is a job for a plumber.
When the pump is the problem
If the filter is clean, the disposal and air gap are clear, the hose isn't kinked, and the sink drains fine, the problem is probably inside the dishwasher:
- •The drain pump may be jammed by debris like broken glass or a fruit pit, or it may have failed. A humming sound during the drain phase with no water moving is a common sign.
- •The check valve, a small flap that stops water flowing back into the dishwasher, can stick.
- •The control or wiring may not be sending power to the pump.
These are jobs for a technician, and they usually involve removing panels or pulling the dishwasher out of the cabinet.
A note about built-ins and apartment kitchens
In apartments and condos, the dishwasher is often wedged into tight cabinetry with a shared drain, and a slow drain can back up into the sink or leak into the cabinet below. In multi-unit buildings, water can reach the unit downstairs. If you see water under the sink or around the base of the dishwasher, shut off the water supply valve under the sink and let your building manager know.
If the dishwasher came with your rental, repairs are usually the landlord's responsibility. Report it in writing.
How a technician diagnoses it
A technician will usually check the filter and sump first, then the drain hose and connections, then test the drain pump and check valve. If the pump receives power but doesn't move water, it's blocked or failed. If it doesn't get power, the control or wiring is the issue. You can read more on our dishwasher repair page. If your problem is cloudy glasses rather than standing water, see our guide to hard water and cloudy dishes.
Preventing drain problems
- •Scrape food off plates before loading. Bones, seeds and labels are common pump jammers.
- •Clean the filter every few weeks.
- •Run the garbage disposal before starting the dishwasher.
- •Clean the air gap cap now and then.
- •Don't store bulky items under the sink that can press on the drain hose.
Frequently asked questions
Is some water in the bottom normal?
A small amount of clear water in the sump area is normal on many models. An inch or more of dirty water isn't.
Can I pour drain cleaner into the dishwasher?
No. Chemical drain cleaners can damage the pump, seals and hoses, and they're hazardous to handle.
Why does my dishwasher drain only sometimes?
An intermittent clog, like a partly blocked filter, hose or air gap, is the most common cause. A pump that's starting to fail can also be inconsistent.