A little water left in the bottom of the tub after a cycle is normal on many models. A few centimetres of standing water is not, and it means your dishwasher isn’t draining properly.
If you have a Bosch dishwasher or a KitchenAid dishwasher, our brand pages list the drain codes we see most.
Most of the time, the cause is a blockage you can clear yourself. Work through these checks in order. They go from the most common, easiest fix to the ones that need a technician.
IN THIS ARTICLE
Clean the Filter
Most dishwashers have a filter under the lower spray arm. Food particles, labels and broken glass get caught in the filter, and a clogged dishwasher filter is the most common reason a dishwasher won’t drain.
Pull out the lower rack, twist the filter out, and clean the dishwasher filter by hand under warm water with a soft brush. Lock it back in firmly.
If it’s loose, debris can get past it into the pump.
How often? If you rinse dishes lightly, once a month is a good habit. If you load plates with a lot of food left on them, check it every week or two.
Check the Drain Hose
The drain hose runs from the back of the dishwasher to the sink drain or garbage disposal. Look under the sink for kinks or a hose pushed flat by stored items.
Many installs loop the hose up high under the counter, which helps stop dirty sink water from flowing back in. If that loop has slipped down, refasten it.
Run the Sink and the Garbage Disposal
If your dishwasher drains into a disposal, run the disposal for a few seconds. Then run water in the sink and watch whether it drains freely.
A slow kitchen sink drain often shows up first as a dishwasher that won’t drain, because they share the same pipe. If the sink itself is backing up, that’s a plumbing clog, and clearing it usually clears the dishwasher too.
New Disposal? Check the Knockout Plug
New garbage disposals come with a plastic plug sealing the dishwasher inlet. If a disposal was just installed and the dishwasher stopped draining right after, the plug was probably never knocked out. This is a quick fix, but follow the disposal maker’s instructions.
Check the Air Gap, if You Have One
Some kitchens have a small chrome cap on the sink deck next to the faucet. That’s an air gap. Pull the cover off and clear any debris inside. If water spurts out of it during a cycle, it’s blocked.
Run a Rinse-and-Drain Cycle
After the checks above, run a short rinse or the drain/cancel setting (check your manual). Listen during the drain stage. Steady draining means you’ve fixed it. A hum with no water moving, or no sound at all, points to a part.
When It’s a Part, Not a Clog
If the filter, hose, sink and air gap are all clear and water still sits in the tub, the usual causes are:
- A failed drain pump, or its impeller jammed by a piece of glass or a bone
- A drain valve or check valve stuck closed, which stops the water from draining even when the pump runs
- A control or sensor fault, so the drain stage never starts
A service technician needs to test these to confirm which part it is, and the pump is often reached from underneath the dishwasher. A typical drain pump repair costs about $180–$340 with parts and labour.
Don’t Do These
- Don’t pour drain cleaner into the dishwasher. It can damage the pump and seals.
- Don’t use regular dish soap in the machine. The suds can stop draining and leak out the door.
- Don’t keep running cycles on a dishwasher that’s holding water and leaking at the same time.
Signs It Needs a Repair Soon
- Water keeps coming back in the bottom of the tub after you’ve cleaned the filter.
- The dishwasher stops partway through and shows an error code.
- You hear grinding or a loud hum during the drain stage.
- Water appears on the floor in front of the door.
Any of these means the dishwasher problem is past a simple clog.
When to Call a Technician
Call if the dishwasher still holds water after all six checks, if it’s leaking, or if you hear the pump humming without draining.
Got a washer that won’t drain too? The checks are a lot like these.
We find the cause, give you the price before any work begins, and back completed repairs with our 1-Year Parts & Labour Warranty.
Dishwasher repair in Vaughan Call 1-888-642-0352 Book online Book a dishwasher installation
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