Down the Drain: 10 Reasons Why Your Dishwasher Isn't Draining

When your dishwasher isn't draining, it can add one more layer of stress to your life. Who wants to worry about dishes piling up or having to scrub by hand after every meal when you have bills to pay and a life to live?

In the following article, we'll be helping you troubleshoot this annoying issue. Time to unload!

1. Dirty Filter and Trap

Ensure if your dishwasher has a filter. Look for the model name of your dishwasher on the inside of the machine. Google what you find, and locate the owner's manual or how-to videos to determine the specific location.

It's often just below the revolving piece under the lower tray. Once you've found it, lift it out of its holding spot and check the sump underneath for any additional food particles.

Your last move in this sequence if the dishwasher isn't draining water is to wash the filter thoroughly and replace it. Then, do another run and see if there are any improvements.

2. Liquid Detergent

Another possible culprit, if the dishwasher isn't draining completely, is to check the type of detergent you're using. Most machines are made for powder detergent.

Now, you've probably used liquid detergent in a pinch if you're like most of us. While it does a fine job cleaning your dishes, the liquid can create so many suds that water can have a hard time properly draining after the cycle.

The simple fix here is to put in the type of detergent intended. If you stay the liquid route, you'll want to reduce the amount you're using, provided that's the issue.

3. Garbage Disposal Blockage

Another thing to check if you find yourself asking why my dishwasher isn't draining is the garbage disposal. There's a hose connecting your dishwasher to the garbage disposal. This hose allows the overspill somewhere to go.

If your garbage disposal is blocked with food or grease, then it can delay the movement of water out of the dishwasher. This causes the standing water effect.

You'll want to check your garbage disposal thoroughly for food particles. Sometimes simply letting it run for a few seconds can take care of the problem. If it doesn't, it may be time to clean your drains.

4. Clogged Air Gap

If your name-brand Bosch or Whirlpool dishwasher isn't draining, it can be especially frustrating. That's especially true when you haven't had it long enough to be experiencing the slow-drain issue.

Fear not, however. You probably don't have to go to battle with the Warranty Department just yet. Instead, consider cleaning the air gap.

The air gap is denoted on your sink by a small cylindrical covering that unfastens and houses the (usually white) air gap itself. Grab some tweezers and a small brush to remove obstructions and grime. Then, run the dishwasher for a cycle and see if the situation improves.

5. Kinks or Clogs in the Drain Hose

Fats, oils, and greases may be the most common drain issues you'll experience likely to have a bearing on slow draining from the dishwasher. However, they're not the only garbage disposal-related items of note.

What you may need to do is replace the connecting hose that runs from the dishwasher into the disposal. This can become kinked or clogged. When that happens, it slows or impedes the water's path.

6. Faulty Drain Hose

You may have tried all that, though, with limited results. While you're examining the drain hose, check the connection points and the strength and stability of the hose itself.

Oftentimes, you can fix kinks and clogs without the need for a new hose. Sometimes you can't.

If you need to replace it, parts aren't too expensive. However, few are confident enough in their repairs ability to do it themselves. If that sounds like you, then you'll need to factor in the cost of labor as well.

7. Aged Plumbing

Most issues with dishwashers being slow to drain are easily and cheaply fixable. In time, however, your plumbing will wear out. Colder months can be especially harsh on older plumbing.

If you have tried everything in this article with the same results, it's time to consider the possibility of a plumbing overhaul. The cost of replumbing your home is significant but can vary based on the type of piping used. Copper is recommended for longevity, but there are other options out there.

Word to the wise — plumbing is a special skill you should leave to the pros to avoid the DIY temptation. The only exceptions to this rule are if you're naturally talented at plumbing or if you've taken the classes and attained the certifications needed.

8. Intact Knockout Plug

Unfortunately, user manuals aren't always that forthcoming on the little details when DIYing some part of your garbage disposal installation. This may have happened to you if you're experiencing slow dishwasher drainage on a newer unit.

That culprit is the knockout plug. Something companies like Bosch and Whirlpool can overlook when telling you how to install.

Remember that drain hose that connects the dishwasher to the disposal? Remove it. What you'll find is a port that has the so-called "knockout plug" inside of it.

Run a blunt instrument into the hole. Smack it a few times with a hammer until the plug falls into the disposal. Then, either remove it with your hand from the sink or grind it down by running the unit.

Grinding it down will be loud at first but harmless to the disposal itself. After the plug is released, water should start draining more quickly, thus eliminating the standing water effect, provided that's your issue.

9. Frozen Valve

You could be experiencing a faulty water inlet valve. This valve, found in the wiring behind the control panel and the bottom panels, can freeze up or give out.

When it does, it will either have trouble shutting off the flow of water into your dishwasher or it won't provide access at all. If the former, then that could account for why you're experiencing standing water.

10. Power Source Failure

Have you checked the outlets or breakers? Are they working properly? If all else fails, this may be what's keeping your dishwasher from properly draining.

If You Are Unsure Why Your Dishwasher Isn't Draining

The "dishwater isn't draining" malfunction is a frustrating one, but don't allow it to consume you. Take action!

Schedule maintenance or checkups with a qualified professional today!