If a dishwasher is not draining, check these in order: the filter and drain basket at the bottom of the tub, a kinked or clogged drain hose, a garbage disposal knockout plug that was never removed, a blocked sink drain or air gap, and finally the drain pump. Most drain problems are a clogged filter or a kink in the hose. A dishwasher that has never drained properly since installation usually points to the hose loop, the air gap or the disposal plug. Stop the cycle, switch off power, and bail out standing water before you start.
PCBy the Pixl Canada install team. Updated . 7 min read. Prices in Canadian dollars, before tax.
- Eight causes, ranked by how common they are
- A check-in-order table
- Bosch and other brands: what is the same
- When it is an installation fault
- Start with the filter and the hose. They fix most cases.
- A new dishwasher that never drains often has an unremoved disposal knockout plug.
- A drain hose needs a high loop or an air gap so dirty sink water cannot flow back.
- Do not pour chemical drain cleaners into a dishwasher.
Why is my dishwasher not draining, and what do you check first?
| # | Cause | Quick test | Fix |
|---|---|---|---|
| 1 | Clogged filter or drain basket | Remove the lower rack and look at the filter | Take it out and rinse off food and grease |
| 2 | Kinked or pinched drain hose | Pull the dishwasher forward slightly and look behind it | Straighten the hose so it is not crushed |
| 3 | Clogged drain hose | Disconnect the hose and rinse water through it | Clear the blockage |
| 4 | Garbage disposal knockout plug not removed | Common on a new install or after a disposal swap | Remove the plug inside the disposal inlet |
| 5 | Blocked air gap | Look at the small cap on the sink or counter | Lift the cap and clean it |
| 6 | Blocked sink drain or disposal | Does the sink drain slowly too? | Clear the sink line or run the disposal |
| 7 | Hose without a high loop | The hose runs low under the counter | Raise the hose to the underside of the counter, or add an air gap |
| 8 | Failed drain pump or motor | You hear humming but no pumping | A repair or replacement for a pro |
How do you fix a dishwasher that will not drain?
- Stop the cycle and turn off power at the breaker or unplug it.
- Bail out standing water with a cup and towel.
- Clean the filter and drain basket in the bottom of the tub.
- Check the hose under the sink for kinks, then disconnect it into a bucket and rinse it.
- Check the disposal knockout plug if the dishwasher connects to a garbage disposal.
- Clean the air gap if you have one.
- Reconnect everything, restore power and run a short rinse cycle.
Bosch, Whirlpool and other brands follow the same logic. Filters sit in slightly different places, so use your manual to find yours. For more on clearing the hose, see how to install a dishwasher, which covers the high loop and air gap.
When is it an installation fault rather than a clog?
| Sign | Likely installation issue |
|---|---|
| It never drained well since it was new | Knockout plug left in, or no high loop |
| Dirty sink water appears in the tub | Missing high loop or air gap |
| The hose is long and sagging | The loop is low or the hose is kinked |
| Water leaks at the connection | A loose clamp or the wrong fitting |
Pixl installs dishwashers for $180 with a new water inlet hose, a 6 ft drain hose is $30 and an installation kit is $30, before tax. We connect to the existing water supply and drain; a new line is work for a licensed plumber. See dishwasher installation, installation cost and who can install a dishwasher.
When should you call a pro?
Call a pro if the dishwasher hums but does not pump, if you see leaks, if the drain line is clogged beyond the dishwasher, or if you are not comfortable working with power and plumbing. A plumber handles clogged household drains, and an appliance technician handles pump faults.
Dishwasher not draining: frequently asked questions
Why is my dishwasher not draining?
Most often a clogged filter or a kinked drain hose. On a new install, check the disposal knockout plug and the high loop or air gap.
How do I drain a dishwasher with standing water?
Turn off power, bail out the water, clean the filter and drain basket, then check the hose and run a rinse cycle.
Can I use Drano in a dishwasher?
Not recommended. Chemical cleaners can damage seals and hoses. Clear blockages by hand.
Why did my new dishwasher not drain?
The garbage disposal knockout plug may still be in place, or the hose may lack a high loop or be kinked.
What is a high loop?
Raising the drain hose to the underside of the counter before it drops to the drain, so dirty sink water cannot flow back.
Can Pixl fix a drain connection?
Send a photo of the connection under the sink to (587) 899-7495 and we tell you what we would do. Pixl dishwasher installation is $180, and you pay after the job.
Installing or replacing a dishwasher?
$180 with a new water inlet hose, before tax. You pay after the job.
How to disconnect a dishwasher
Appliance installation in Canada
How to install a dishwasher
Dishwasher installation cost
Who can install a dishwasher
How to clean a dishwasher and filter
How to choose a dishwasher
Sources and method. General troubleshooting order used by appliance manuals and installers. Check your dishwasher’s manual for model specifics. Pixl prices were checked in October 2026, in Canadian dollars, before tax.
About Pixl Canada. Pixl Canada is an installation company based in Edmonton, Alberta, serving cities across Canada with TV mounting, security cameras, appliance installation and smart home setup. Call or text (587) 899-7495. Open Monday to Saturday 8am to 8pm and Sunday 9am to 7pm.