Standing water at the bottom of your dishwasher after a cycle is frustrating, and it usually means one of a small number of things. We diagnose dishwasher repair in Edmonton calls like this every day. Here are the six causes we see most often, in rough order of frequency.
1. Clogged Filter and Food Trap
The most common cause by a wide margin. Every dishwasher built after about 2010 has a removable cylindrical filter at the bottom of the tub. It catches food particles before they reach the pump. When it's not cleaned regularly — monthly is the recommendation — it restricts water flow to the point where the machine can't drain properly. Remove the filter, rinse it under the tap, and run another cycle. This fixes the problem in a significant number of cases without any repair needed at all.
2. Drain Hose Kinks Behind the Unit
The drain hose runs from the pump behind the dishwasher to either the sink drain or the garburator. If the dishwasher was recently moved, installed, or bumped, the hose can develop a kink that restricts drainage. Pull the unit out slightly and check the hose. It should have a smooth curve with no sharp bends. A hose that kinks in the same spot repeatedly may need replacement.
3. Air Gap and Garburator Connections
Many older Edmonton homes have a chrome cylinder mounted beside the kitchen tap — this is the air gap, a backflow prevention device required by plumbing code in some installations. The air gap can become clogged with debris over time. If you have one, remove the cap and clean the interior. If the dishwasher drains into a garburator, make sure the knockout plug was removed when it was installed. A missing knockout removal is a surprisingly common cause of drainage failure after a new garburator is installed.
4. Failed Drain Pump
The drain pump expels water from the tub at the end of the cycle. When it fails, you'll often hear the machine humming or buzzing during the drain phase without the water actually moving. Some dishwashers display an error code — Bosch's E24 and E25 point to drain pump issues. A failed pump requires replacement. This is a same-day repair for the most common brands.
5. Hard-Water Scale on the Check Valve
Edmonton's water is moderately hard, and over time mineral deposits can build up on the check valve — a small flap that prevents drain water from flowing back into the tub. If the valve sticks open due to scale, water re-enters the tub after draining, leaving what looks like a partial drainage failure. Cleaning or replacing the check valve resolves it.
6. Failed Drain Solenoid (Older Models)
Older dishwashers, particularly those more than 10 to 12 years old, may use a drain solenoid rather than a dedicated drain pump motor. When the solenoid fails, the drain flap doesn't open and water stays in the tub. This is less common on newer machines but worth checking on older Kenmore, older Frigidaire, and older Whirlpool models.
When to Call for Dishwasher Repair
If you've cleaned the filter, checked the hose, and the machine still won't drain, it's time for a diagnosis. The drain pump, check valve, and solenoid failures listed above all require opening the machine and testing components — work that's worth doing properly. See the most common appliance problems Edmonton technicians see for a broader look at what fails most often. When you're ready, book a same-day repair and we'll get it sorted.