Dishwasher Backing Up Into Sink

It may not be the end of the world, but it is a real pain if your dishwasher is backing up into the sink. Especially after having a nice dinner, when you are in the mood of enjoying your family time or personal time, you would want to let your dishwasher do all the work. After all, that’s the main reason you have a dishwasher. It is really annoying to see your clean sink getting messy or even worse, flooded with dirty water.

Your dishwasher and sink drainage line are interconnected and any minor issue in the main water line or drainage line can cause your dishwasher backing up into sink frequently. In this article, we will go into details of the possible reasons which may cause your dishwasher backing up into the sink and we will discuss what can you do about them.

4 Possible Reasons Your Dishwasher Backing Up

There are mainly 4 places from where your dishwasher drainage problem can come about. They are the dishwasher, the garbage disposal line, the sink, and the air gap line. We will discuss every possible place in the following sections.

Dishwasher Maintenance Basics

Before attempting to solve any of your dishwasher problems, it is important to cut off the power line of your dishwasher and any other plumping appliances like garbage disposal pump. Otherwise, there will be a chance of electrocution and other types of injuries. Another primary knowledge in this regard is understanding the water and drainage flow of your kitchen. The water drainage line of your sink and dishwasher is the same. So any blockage in the main drainage line will cause an overflow of water to your sink and dishwashers. Therefore, you should check the main drainage line before looking into the following places.

1. The Dishwasher Blockage

The first thing to check in case of dishwasher backing up into the sink is the dishwasher drainage line. It is okay to have some standing water in the dishwasher drainage line, but if there is constant water in the mouth of the dishwasher drainage line, then the dishwasher might not drain properly. You can check if the dishwasher is draining properly or not by removing the drainage hose from the mainline and running the dishwasher separately. You can check it visually by the water flow from the hose. Don’t forget to place a bucket underneath it.

Another thing to consider in this regard is the detergent usage in your dishwasher. Using the correct detergent of the proper amount is crucial for getting the best out of your dishwasher. If, in doubt, you can make your own detergent for the dishwasher. Otherwise, it will clog the dishwasher in the long run. You can also make your own dishwasher detergent all by yourself if you are up for it.

2. The Sink Blockage

It is very possible that your sink is clogged and it is causing water backing up into dishwasher. You can use any of the following methods or a combination of them to resolve this issue.

  • Running the Garbage Disposal

    You should not drop all types of food waste like eggshells, leftover pasta into the sink. This practice will eventually cause you a lot of troubles. However, it is good to run your garbage disposal pump a couple of minutes before using the dishwasher.

  • Cleaning the Sink Regularly

    You should clean your sink regularly to prevent any sorts of clogging. You can run down slightly warm water in this regard. There are many sink cleaner products which you can purchase.

  • Snaking the Sink

    Sink snake is the ultimate solution to your sink cleaning problem. It can handle which your garbage disposal can not.

4. Blocked Air Gap

The air gap is the protective measures which prevent the sink water backing up into the dishwasher. If the air gap is clogged then it is very likely that your dishwasher will get contaminated by dirty water. You can easily clear the air gap blockage by opening the cover of the gap and snaking it with the sink snake.

5. Jammed Garbage Disposal

Jammed garbage disposal is a very potent cause of your dishwasher problems. Your dishwasher is connected with the garbage disposal pump through the drain plug. It is very common that after installing a garbage disposal pump, the drain plug is left untouched. Simply, remove the drain plug to resolve this issue. You can also call in a professional if there arises any complexity. A blockage in drainage line may occur for many other reasons as well and can be fixed with simple steps.

These are the common reasons that can cause frequent dishwasher problems like dishwasher leaking or water coming back up kitchen sink. The common rule of thumb in this regard is, don’t treat your sink and garbage disposal pump as the trash can. If you maintain your dishwasher and garbage disposal pump properly you don’t have to worry about kitchen sink overflowing or dishwasher sink draining problem in near future.


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