Got a Dishwasher that Won’t Drain? Here’s How to Troubleshoot the Problem

Less than a year ago, I walked into the kitchen, opened the dishwasher and saw a sight I’d seen before but hoped I’d never see again – lots of water filling the bottom of my dishwasher. This same problem had happened many years before. At the time, I was renting a home. This time around we owned both the home and the dishwasher. The problem, however, was the same: the dishwasher would not drain.

Both times, we fixed the problem ourselves. Each time, the cause was different but the problems were easy to fix. Hopefully, you can use this information to figure out why your dishwasher won’t drain and find a solution. While I can’t absolutely guarantee you’ll be able to fix the problem yourself, it is certainly worth a try before shelling out dollars to a dishwasher repair person. So give it a try!

Here is the step by step system I use when a dishwasher won’t drain:

First, be sure you know what type of dishwasher you have (not the brand name but the type – either direct drive or forward reversing).

Depending on the age of your dishwasher, it could be either a direct drive or forward reversing type. We’ve had both. Direct drive dishwashers simply keep going as the water drains but forward-reversing ones have motors which stop and then start (moving in the opposite direction) to drain water out of the dishwasher. It helps to know what type of machine you have. Obviously, if the motor isn’t reversing properly, that could be the cause of a problem right there. But let’s hope that is not the case.

Next, think about whether you’ve installed a garbage disposal recently and if the dishwasher stopped draining right after you installed the disposal.

Many dishwashers won’t drain or seem clogged after a garbage disposal is added to the sink area. Happily, this is not only a common problem but one which is usually resolved quickly. You’ll simply have to check a piece called the knock-out plug. You can see what that looks like here: www.applianceaid.com/food.html#plug

Okay, so was your disposal installed without taking out the knockout plug? Oops! Simply remove it and you are good to go. Your dishwasher should now drain smoothly. Simple.

I know about this particular issue because we once installed a garbage disposal ourselves, trying to save money, and didn’t remove that important plug. One very wet kitchen floor later…we learned a lesson.

If that doesn’t work, you’ll need to check some very specific parts on your dishwasher to try and fix the problem and get it to drain again.

To do this, it helps to find your particular model and get a mental image of each part. It isn’t absolutely necessary but does help in picturing your specific model and the parts described in the rest of this article. Here’s a good place to do that: www.partselect.com/Locate-Parts.aspx. At this site, you can find your particular brand of washer and each part.

If you still have any confusion, you can call a specialist there (free) to get suggestions and alternate names for each part. The number is easily found at the site. I’ve found this to be one of the best ways to diagnose dishwasher problems, fix drainage issues and/or order necessary parts.

Without further ado, let’s consider some other relatively simple reasons why your dishwasher may stop draining:

Many dishwasher actually drain under your sink. One clue that this may be the case? Water bubbles up into your sink when the dishwasher runs. If that drain is clogged up, that can keep your dishwasher from draining. Again, this is a fairly easy fix and certainly within the abilities of the average homeowner, even one who isn’t adept at home repairs.

So try disconnecting the drain from under your sink and see if there are water deposits, including lime build-up, or other matter such as food debris. Clear the drain and reconnect it. While you are at it, check the hose that may run from your dishwasher to the sink. You’ve just taken care of two potential causes of a dishwasher that won’t drain.

The dishwasher basket could be the problem

Okay, you’ve gone through the list above and haven’t added a new garbage disposal or found any problems in the drain under your sink or in the tube connecting your disposal to your sink. Now it is time to look at your dishwasher basket. Make sure you know where it is by referring to the website listed above and by knowing how it looks in your particular dishwasher model.

As a general rule, most baskets are held in place by some screws. You’ll need to take a wrench or similar tool and take out those screws.
Important tip here – work slowly, have patience and expect this to take some time. It is not difficult, however. Once you remove the basket, you may see a flap inside and..yes..you need to take that out (gently), if possible. At this point, you should know if these parts need cleaning. The smell and gunk in there will be a sure sign. If things are very clean, the problem may not be with your dishwasher basket.

However, if there is a lot of debris, food and indescribable gunk in there, it is due for a good cleaning. Wipe down each part with either paper towels or old rags and clean them thoroughly, taking care not to bend or reshape them. You want them to fit together easily afterward. After cleaning, put them back in place. If there was a lot of food in there, take hope…because that is a sign that his could be the problem. After you finish cleaning these parts, congratulate yourself om possibly saving the time and expense of a service call. You may just have solved the problem and maybe your dishwasher will drain nicely now.

Of course, you’ll want to siphon out the old dirty water first, especially if it has plenty of debris in it.

What if these steps don’t work?

You might still be able to fix the problem yourself but I would strongly suggest calling in a specialist at this point. Why? Because you could have motor issues, pump problems or even something wrong with the dishwasher timer. Again, you may be able to fix these things yourself but they are beyond what I consider normal for the typical homeowner. Plus, if you install a part wrong you could void the warranty! Better to use a repair person. If you want to try and fix it yourself, check out these parts: drain valve, belt, motor, timer and solenoid. Most of these parts would have to be ordered and you could not repair a clogged dishwasher that won’t drain quickly.

Once you get your dishwasher unclogged and it drains again, how can you prevent another unpleasant surprise?

No one wants to hear a son, daughter or husband saying, “The dishwasher won’t drain” (trust me on this). It never happens at the right moment, on a leisurely summer afternoon. Instead, it is likely to occur when you are about to have guests, are half-dressed and in no mood to deal with a water-soaked kitchen.

How to prevent your dishwasher from getting clogged

Once you solve the problem, put the odds on your side. Before running your dishwasher, take some time to turn on your garbage disposal and run hot water through it. Do this even if you don’t have food in your sink. This clears out any excess grease and leaves the hose and pipes as clean as possible. Consider using a drain cleaner if you have hard water or mineral deposits in your lines.

I also run vinegar through my dishwasher at least once a month. I can see the gunk and deposits that come out each time…and plenty does! Some people swear by lemonade Kool-aid drink mix (at least two of my friends use this) but I confess I have not tried this. I do use Glisten to keep water spots and mineral deposits to a minimum. I also check my dishwasher basket regularly as well as the sink pipes and hoses to and from the dishwasher. Routine maintenance goes a long way!