Dishwasher Won’t Drain? 5 Checks to Make Before You Call an Ottawa Plumber
Opening the dishwasher to find a tub of grey, standing water is a common kitchen problem across Ottawa, from Barrhaven and Kanata to Orleans and Nepean. Most of the time the cause is a blockage somewhere between the dishwasher and the kitchen drain, and the first few checks cost nothing and need no tools beyond a screwdriver and a towel.
If the water is already backing up into your sink, skip ahead and book a kitchen drain clog repair in Ottawa or call 613-227-7465.
Key takeaways
- Start simple: clean the filter, then check the drain hose, the air gap or high loop, the garbage disposal knockout plug and the sink drain, in that order.
- Safety: turn the dishwasher off at the breaker or unplug it before reaching into it.
- Skip the chemicals: liquid drain cleaners can damage dishwasher parts and are a hazard for the person who works on the drain next.
- Call a plumber if the sink also drains slowly, if water returns after you clear the dishwasher, or if the unit is newly installed.
Why Does a Dishwasher Stop Draining?
A dishwasher drains through a pump, a drain hose and a connection to either the kitchen sink drain or a garbage disposal. A blockage or restriction at any point can leave water in the tub. Food debris, grease, a kinked hose, a hose without a proper high loop, or a clog in the kitchen drain line are the usual suspects.
A small amount of water around the filter can be normal in some models, so check your manual before deciding something is wrong.
The 5 Checks, in Order
Before you start: Switch off the dishwasher at the breaker or unplug it. Put towels down and scoop standing water out with a cup first.
Clean the filter and the sump
Remove the lower rack and lift out the filter, following your manual. Rinse it under the tap and clear any food, glass or labels from the sump below it. A clogged filter is the most common cause and the easiest to fix.
Check the drain hose for kinks
Pull the dishwasher forward slightly if you can, or look under the sink. The drain hose should run freely without a sharp bend or crushing. Straighten any kink and make sure the hose is not pinched against the cabinet.
Look at the air gap or high loop
Some homes have an air gap, a small cylinder on the sink or counter. Lift the cap and clear any debris. If there is no air gap, the hose should rise in a high loop under the counter before dropping to the drain, which helps stop dirty sink water flowing back.
Check the garbage disposal knockout plug
If the dishwasher drains into a garbage disposal, the disposal inlet has a plug that must be knocked out when the dishwasher is connected. A plug left in place after a new disposal or new dishwasher installation blocks drainage completely. Clear the disposal of food at the same time.
Test the kitchen sink drain
Run the tap and watch the sink. If it drains slowly or gurgles, the clog is in the sink drain line, not in the dishwasher. This is the point where most homeowners need a plumber with a drain machine.
Tip: After each check, run a short drain or rinse cycle. Stopping as soon as the water leaves tells you which check solved it.
Symptom Guide: What Is Probably Wrong
| What you see | Most likely cause | Next step |
|---|---|---|
| Standing water, sink drains fine | Clogged filter or sump, kinked hose | Checks 1 and 2 |
| Water in the dishwasher and a slow sink | Clog in the sink drain line | Check 5, then call a plumber |
| Dishwasher never drained since installation | Knockout plug still in the disposal, or hose set up wrongly | Check 4 and the hose loop |
| Sink water or grey water rises into the dishwasher | Missing high loop or blocked air gap | Check 3 |
| Humming from the dishwasher but no drain | Blocked pump or a pump that needs repair | Appliance technician or plumber to diagnose |
When to Stop and Call a Plumber
Stop and call if the water keeps returning after the checks, if both sides of a double sink back up, if there is a sewage smell, or if you are not comfortable pulling the dishwasher out. A plumber can clear the drain line, correct the hose connection and confirm the unit is properly connected. If you have just had a dishwasher fitted, our dishwasher hookup service in Ottawa can check the installation, and garbage disposal repair is available when the disposal is the problem.
If the pump or controls on the appliance itself have failed, that is usually a job for an appliance repair technician rather than a plumber, and we will tell you that honestly after diagnosing the drain side.
Dishwasher still full of water?
John The Plumber can clear the drain line and check the connection in Ottawa homes.
Dishwasher Drain FAQs for Ottawa Homeowners
Why is there standing water in the bottom of my dishwasher?
Is a little water at the bottom of a dishwasher normal?
Can I pour drain cleaner into the dishwasher?
Why did my dishwasher stop draining after I installed a new garbage disposal?
Does a slow kitchen sink affect my dishwasher?
Should I call a plumber or an appliance repair technician?
How do I contact John The Plumber in Ottawa?
Get Help With a Dishwasher That Will Not Drain in Ottawa
Call 613-227-7465 or visit johntheplumber.ca to book a plumber.
