A dishwasher that won’t drain is most commonly caused by a clogged drain filter, a blocked air gap or garbage disposal knockout plug, or a failing drain pump. Kitchen sink clogs can also cause dishwasher backups since many units share a drain line.
Common Reasons Your Dishwasher Is Not Draining
Clogged Drain Filter
Most modern dishwashers have a removable filter at the bottom of the tub that catches food debris. When it’s full, water can’t drain properly.
Blocked Garbage Disposal Knockout Plug
If your dishwasher was installed alongside a new garbage disposal, the knockout plug connecting the two may not have been removed, blocking drainage entirely.
Clogged Air Gap
The small air gap fitting near your kitchen faucet can become clogged with food particles, which prevents the dishwasher from draining correctly.
Failing Drain Pump
Like a washing machine, dishwashers use a pump to push water out. A worn or jammed pump will leave standing water in the tub.
Kinked or Clogged Drain Hose
The hose that connects the dishwasher to your kitchen drain can become kinked during installation or clogged with grease and debris over time.
Clogged Kitchen Sink Drain
Since dishwashers typically share a drain line with the kitchen sink, a clog anywhere in that line can cause water to back up into the dishwasher.
What You Can Check Yourself
- Remove and rinse the dishwasher’s drain filter (check your manual for its location)
- Check the air gap near the faucet for visible clogs
- Run the garbage disposal to clear any blockage in a shared line
- Inspect the drain hose behind the dishwasher for kinks
When You Should Call an Appliance Repair Technician
If the filter, air gap, and hose are all clear but water still isn’t draining, the drain pump itself may have failed and should be inspected by a professional.
Dishwasher Repair in Lake Zurich, IL
Our technicians proudly serve Lake Zurich and the Northwest Chicago Suburbs, resolving drainage issues so your dishwasher gets back to work fast. Schedule Dishwasher Repair today.
Frequently Asked Questions
Why is there standing water in my dishwasher after every cycle? This is a strong sign of a clogged filter, blocked air gap, or a failing drain pump.
Can a clogged sink cause my dishwasher not to drain? Yes, since most dishwashers drain through the same line as the kitchen sink.
Is it safe to run the disposal to fix a dishwasher clog? Yes — running the disposal briefly can clear debris in a shared drain line, which often resolves the issue.
How often should I clean the dishwasher filter? Once a month is a good general guideline, more often if you don’t pre-rinse dishes.