When your dishwasher won’t drain completely, it can throw off your whole routine. We’ve been there. It’s frustrating to open the door expecting sparkling dishes, only to find a pool of dirty water at the bottom. The good news is, most drainage issues can be fixed without tearing the machine apart or replacing major parts.
In this guide, we’ll walk through the most common reasons your dishwasher isn’t draining fully, what you can do before calling for help, and how to avoid bigger issues later. We’ll also point out signs that something more serious might be going on.
Start With the Basics: What Should Happen
Before we dig into troubleshooting, let’s look at how things are supposed to work. A dishwasher fills with water, washes the dishes, then drains the dirty water out through a hose connected to your kitchen plumbing. If any part of that process is blocked, clogged, or misaligned, drainage issues are likely.
Most importantly, drainage usually happens in short cycles during and after washing. If there’s still a bit of clean water in the sump area near the filter, that’s normal. However, standing dirty water covering the base? That’s a clear problem.
Step One: Check the Filter and Drain Area
One of the most common causes of poor drainage is a clogged filter or food buildup in the drain area. Over time, small particles of food, grease, and even bits of broken glass can collect in the bottom of the unit.
Firstly, remove the bottom rack and inspect the filter. You’ll usually find it under the spray arm or right in the center of the floor. In some cases, it twists out by hand. To clarify, there might be a coarse filter on top and a finer screen underneath, so remove all parts for a full check.
Rinse the filter thoroughly under running water and gently scrub off any buildup with an old toothbrush. Secondly, look into the sump well where the filter sits. If there’s gunk or debris, scoop it out with a spoon or a cloth. Most importantly, never use anything sharp that could damage internal parts.
Step Two: Inspect the Drain Hose
If your filter is clean but the water still won’t leave the dishwasher, the problem might lie in the hose that carries water away. This hose connects from the bottom of your dishwasher to the garbage disposal or sink drain pipe.
Firstly, we want to check if this hose is kinked, clogged, or blocked. Pull the unit slightly forward if you can and look behind it. Be careful with the water line and power connection. If the hose is pinched or looped the wrong way, straighten it out.
Secondly, disconnect it carefully from the sink end and run water through it using your tap or a turkey baster. If it’s slow to drain or blocked entirely, you’ll feel resistance. In that case, push a long flexible brush through it or use a vacuum to dislodge clogs.
For more complex drainage issues, or if your dishwasher won’t even start the drain cycle, professional dishwasher repair in Calgary may be necessary to safely handle internal pump problems.
Step Three: Look at the Air Gap or High Loop
If your kitchen setup includes an air gap (a small cylinder on your sink next to the faucet), this could be the cause of the drainage failure. Air gaps prevent dirty water from siphoning back into the dishwasher. However, they can become clogged with grease or debris over time.
To fix this, remove the cap of the air gap and clean out any food particles you can see. Use a pipe cleaner or a bottle brush to reach inside. After that, run the dishwasher again to see if the water now drains properly.
On the other hand, if you don’t have an air gap, your dishwasher hose should be looped high up under the sink, usually attached to the underside of the counter. This high loop keeps dirty water from flowing back into the dishwasher. If it’s hanging low or not secured properly, reposition it so it sits above the sink drain connection.
Step Four: Run a Cycle With Vinegar and Baking Soda
After you’ve removed visible blockages, we recommend running a cleaning cycle to break up grease and soap residue that could be slowing drainage.
Firstly, pour one cup of vinegar into a bowl and place it in the top rack of your empty dishwasher. Run a hot water cycle. Then, sprinkle baking soda on the bottom of the tub and run another short cycle. This method can help deodorize and clear away buildup without using harsh chemicals.
This is especially helpful if you notice that your dishwasher smells bad or drains slowly even when the filter is clean. That is to say, cleaning the inside helps with both odor and flow.
Step Five: Listen to the Drain Pump
If everything seems clean but the water still won’t budge, listen closely when your machine runs a cycle. Do you hear the pump engaging when it should be draining? Normally, there’s a distinct humming or whirring sound during that part of the cycle.
However, if you only hear a low buzz or nothing at all, the pump may be jammed or faulty. Foreign objects like bits of glass, paper labels, or even broken pieces of plastic can block the impeller. To inspect this safely, we suggest turning off the power at the breaker before opening the pump access panel underneath.
Pump repairs can be tricky and vary by model. In cases where the pump doesn’t respond or the unit leaks during draining, it’s best to reach out for appliance repair in Calgary before the issue worsens.
Step Six: Check for Garbage Disposal Connection Issues
In some kitchens, the dishwasher drains into a garbage disposal. If that’s the case, a clogged or recently installed disposal could be to blame. Sometimes, the knockout plug in the disposal inlet isn’t removed after installation. Consequently, water from the dishwasher has nowhere to go.
To fix this, remove the drain hose from the disposal and check for a round plastic plug inside. If it’s still there, gently knock it out with a screwdriver and hammer. Be sure the disposal is unplugged and completely off before you do this.
Furthermore, even if the knockout plug is removed, the disposal itself can clog with food waste. Run the disposal with cold water for a full minute and flush out any backups.
Bonus Tip: Use the Right Detergent and Don’t Overload
Not all problems are mechanical. Sometimes, poor drainage stems from bad usage habits. For example, using too much detergent or the wrong kind can cause suds to build up and prevent proper drainage.
Always follow the detergent instructions, especially if you use pods or gels. In addition, don’t overcrowd the racks or block the spray arms. When dishes block the sump area, the water can’t flow down properly.
Keeping a consistent maintenance routine and loading your dishwasher correctly will prevent many common problems before they start.
When It’s Time to Get Help
If you’ve gone through all of the above and your dishwasher still won’t drain, it may be time to bring in someone trained to diagnose the root cause. Electrical issues, broken check valves, or damaged control boards can all stop the drain cycle from completing. In those cases, continuing to run your machine could cause leaks, overflows, or even damage to your flooring.
We’re ready to help you figure out what’s going wrong. You can request help or set up a service visit by filling out our dishwasher repair request and we’ll take it from there.
FAQs
Why is there always some water left at the bottom of my dishwasher?
A small amount of clean water in the sump is normal. It helps keep the seals from drying out. However, if dirty water is pooling above the filter area, that’s a sign of a drainage issue.
Can I use a plunger to fix my dishwasher not draining?
No, plungers are not recommended. They can push water into sensitive parts of the machine or break internal seals. It’s better to check and clean the filter and hose manually.
Should I remove the drain hose myself?
Only if you’re comfortable working around plumbing. Always turn off power and water before starting. If you’re unsure, it’s safer to contact a technician.
How often should I clean the dishwasher filter?
We suggest cleaning the filter once a month, especially if you don’t rinse dishes before loading. That reduces the chance of clogs and keeps the unit running efficiently.
What if my dishwasher smells bad and won’t drain?
Odors are usually a sign of trapped food or grease. Start with a deep clean using vinegar and baking soda. If the smell and drainage issue continue, a clog is likely deeper in the system.