Quick answer
Most dishwashers stop draining because the filter at the bottom of the tub is clogged, the drain hose is kinked, or the sink drain or garbage disposal is blocked. Turn the power off at the breaker, remove the standing water, clean the filter, then check the hose and sink connection. If you just installed a new disposal, the knockout plug inside it is the most likely cause.
Water sitting in the bottom of your dishwasher after a cycle is a common problem. The good news is that many causes are simple and need no special tools. Manufacturers such as Whirlpool, Bosch, Samsung and LG all tell owners to start with the same basic checks before booking a repair.
Work through the checks below in order. Keep your owner's manual nearby, because filters and pump covers differ by model.
Before you start: safety first
Safety: Turn off power to the dishwasher at the circuit breaker. Do not rely on the control panel alone. Whirlpool's guide says to confirm the display and lights are off before you start. If you smell burning, see damaged wiring, or the breaker keeps tripping, stop and call a qualified technician.
- Shut off the water supply valve under the sink (usually on the hot water line).
- Put towels on the floor in front of the dishwasher.
- Wear gloves. Bosch and Samsung both warn that debris in the filter and pump area can be sharp, such as broken glass.
- Do not pour drain-cleaning chemicals into the dishwasher. Whirlpool warns they can damage parts and create safety hazards.
Step 1: Remove the standing water
- Pull out the lower rack.
- Scoop the water into a bucket with a cup or small container.
- Use a turkey baster, sponge or hand pump to remove the water in the sump. The sump is the low well near the filter.
- Pour the dirty water into a sink or toilet.
Step 2: Clean the filter
Bosch says the most common reason a dishwasher stops draining is food debris clogging the filter or the pump. Most modern dishwashers have a filter you can take out by hand.
- Find the filter at the bottom of the tub. On many Whirlpool and LG models, you twist it counterclockwise and lift it out.
- If there is a second (lower) filter or mesh plate, lift it out too.
- Rinse the filters under warm running water. Scrub gently with a soft brush and a little dish soap. Avoid scouring pads, which can damage the mesh.
- Shine a flashlight into the sump. Look for seeds, labels, toothpicks, bones or glass, and remove them carefully.
- Put the filters back. Make sure the lower filter sits flat and the upper filter locks in place. A loose filter lets debris reach the pump.
- Run a short rinse cycle and listen for the drain pump.
Scrape plates before loading and clean the filter regularly. Whirlpool recommends cleaning it more often if you cook and run the dishwasher a lot.
Step 3: Check the drain hose for kinks
The drain hose runs from the back of the dishwasher to the sink drain or garbage disposal. If it gets pinched or bent, water cannot get out.
- Look under the sink. Make sure the hose is not kinked, crushed or sagging.
- Move cleaning products or storage bins that may be pressing on it.
- If a clog is likely, put a pan under the connection, loosen the clamp and pull the hose off. Check the end for debris.
- Flush the hose with warm water. Whirlpool suggests using a flexible plastic line or a soft brush for stubborn clogs, not sharp tools that could puncture the hose.
- Reattach the hose and tighten the clamp snugly, but not too tight.
LG's support page says its dishwasher drain hose must be no more than 3.6 m (12 ft.) long, and its end must be 30 to 100 cm (12 to 40 inches) above the floor. Other brands may have different limits, so check your installation manual.
Step 4: Check the high loop or air gap
Whirlpool says the drain hose must have a proper high loop or be connected to an air gap, as required by local codes. The high loop means the hose rises up and is secured to the underside of the counter before it goes down to the drain. This stops dirty sink water from flowing back into the dishwasher.
- High loop: Check that the hose is still fastened up high. Under-sink work or a new disposal can knock it loose.
- Air gap: This is a small cap on the sink or counter, next to the tap. With the dishwasher off, remove the cover and clear any debris. LG suggests a toothpick or small brush.
If water spills out of the air gap into the sink during a cycle, Whirlpool says the blockage is further down: in the hose from the air gap to the drain, or in the sink plumbing.
Step 5: Check the sink drain and garbage disposal
Your dishwasher drains into the same pipes as your kitchen sink. If those pipes are clogged, the dishwasher cannot drain either.
- Samsung suggests running water in the sink for about 30 seconds. If the sink does not drain, the problem is likely in the home's plumbing, not the dishwasher.
- If you have a garbage disposal, run it with cold water to clear food, then start a drain cycle.
- Check the sink tailpiece and trap for buildup.
New disposal? Check the knockout plug
Whirlpool calls this "a common misdiagnosis" for a clogged dishwasher. New garbage disposals come with a plastic plug sealing the dishwasher inlet. If nobody removed it, water cannot leave the dishwasher at all. LG, Samsung and Whirlpool all list this check for new installations.
Whirlpool's instructions are to knock the plug into the disposal with a hammer and screwdriver, then pull it out with needle-nose pliers. Make sure the disposal is switched off and unplugged first. If you are not comfortable doing this, a plumber or installer can do it quickly.
Step 6: Check the drain pump
The drain pump pushes water out of the machine. Whirlpool's troubleshooting table gives these clues:
| What you notice | Likely cause |
|---|---|
| A little water above the filter | Partial clog in the filter, sump or hose |
| Water up near the door opening | Severe blockage or the pump is not running |
| Humming, but no water moves | Something is jamming the pump impeller |
| Grinding noise | Hard debris, such as glass, in the pump area |
| No pump sound at all | Electrical or control problem |
On some models, you can take off a pump cover to clear debris. Bosch tells owners to remove the pump cover as shown in the owner's manual, then remove debris and water with a sponge. Only do this if your manual shows how. If there is no pump sound at all, that points to an electrical or control problem, which is a job for a technician.
When to call appliance repair
Call a qualified technician or the manufacturer's service line if:
- The dishwasher still does not drain after you cleaned the filter and checked the hose, air gap and sink.
- You hear no pump sound during the drain part of the cycle.
- There is a burning smell, damaged wiring, or the breaker trips.
- Water is leaking onto the floor.
- An error code appears that your manual does not explain.
If the sink itself is also slow or backing up, call a plumber instead of an appliance technician. Repair prices vary a lot by brand, part and company, so ask for a written quote before work starts.
Frequently Asked Questions
Why is there water in the bottom of my dishwasher?
The most common cause is a clogged filter. A kinked drain hose, a blocked sink drain or garbage disposal, or a jammed drain pump can also leave water behind.
Can I use drain cleaner in my dishwasher?
No. Whirlpool warns that drain-opening chemicals can damage dishwasher parts and create safety hazards. Remove the water by hand and clean the filter instead.
My dishwasher stopped draining right after a new garbage disposal was installed. Why?
The knockout plug inside the disposal's dishwasher inlet was probably not removed. It blocks drainage completely. It must be knocked out before the dishwasher hose is connected.
What is a high loop?
It is a section of the drain hose that is raised and fastened to the underside of the counter. It stops dirty water from the sink flowing back into the dishwasher. Some homes use an air gap on the counter instead.
My dishwasher hums but does not drain. What does that mean?
Whirlpool says humming with no draining usually means something is jamming the drain pump impeller. Turn off the power, remove the water, and check the sump for debris. If you cannot reach the pump, call a technician.
Does home insurance cover water damage from a dishwasher?
The Insurance Bureau of Canada says a home policy typically covers water damage caused by an appliance malfunction, such as a dishwasher. The cost to repair the appliance itself is not usually covered. Check your own policy.
Official sources
- Dishwasher Not Draining — Whirlpool Product Help
- Newly Installed Dishwasher Not Draining — Whirlpool Product Help
- Connecting Dishwasher Drain to Garbage Disposal — Whirlpool Product Help
- Dishwasher Not Draining — Bosch
- Steps to Take if Your Samsung Dishwasher Is Not Draining — Samsung Canada
- How to Fix an LG Dishwasher That Is Not Draining (OE Error) — LG
- Water Damage and Flood Protection — Insurance Bureau of Canada
General information only, not professional advice. Rules and prices change, so check the official sources above before you act. Spotted something out of date? Tell us.