Why Is My Sink Filling Up When I Use My Dishwasher and How Do I Stop It?

A dishwasher is a modern convenience that allows you to save time and avoid the mess of washing dishes by hand. Problems with your dishwasher can make it impossible for you to use it and prevent you from getting your dishes clean. 

If you find that your kitchen sink fills up when you run your dishwasher, most of the time it’s due to an improperly sized drain line. It can also be a clogged sink drain, something in the garbage disposal, or even an air gap blockage in the drain line.

So, if your sink fills up when you run the dishwasher, here are some tips to help you stop it from happening again. First, make sure that the drain hose is clear and not blocked by objects or other materials that could cause clogs. 

Second, remove any debris from around your sink so that when water drains out of the drain pipe it doesn’t go into your cabinet or onto the floor. This article goes into detail on these causes, as well as how to fix each one.

If you have a dishwasher and a kitchen sink, it’s not uncommon for the water in one to start overflowing onto the other. 

While this may seem like an inconvenience. It could be indicative of more serious problems that need to be addressed quickly. Here are some possible causes and solutions:

Reason #1: Your kitchen sink drain is clogged

If your dishwasher is filling up, it’s most likely because of a clogged kitchen sink drain. Your dishwasher will fill as much as an inch more than usual and then shut off, leaving you with dirty dishes to clean.

Preventive measures

  • Make sure all of your drains are clear by using a plunger or snake once every month or so. You can also use baking soda at least once every six months if needed (this works best on sinks).

If your dishwasher is filling up, check the following

  • Is the air gap working properly?
  • Is the drain hose connected properly?

Make sure that all of the pipes are connected properly and that there are no leaks. If you have an electric dishwasher, make sure that all of the wires are securely plugged into their respective outlets in accordance with manufacturer guidelines.

If the sink is draining slowly, try using a plunger or snake to clear the drain. You can also use a garbage disposal cleaner if you have one and it’s not clogged. If all else fails, call an expert who can fix whatever’s wrong with them.

Reason #2: Clogged Sink

Clogged sinks are one of the most common plumbing problems.  Clogs often occur when there is dirt in the drain or when someone has dropped something down the drain.  and they can be frustrating to fix. Luckily, there are several ways you can fix these problems yourself.

Quick solution

Declogging a sink without a pro is easy. You can save money by fixing it yourself, and you don’t need any special tools.

So First, turn off the water. Then, take a sponge or rag and soak up as much of the water as you can. If this doesn’t work, you can try using a plunger to force out any remaining clogged substance.

Plunger: A plunger is the most common tool used to unclog a sink. 

Metal hanger: If a plunger isn’t working for you or if there are other objects stuck in the drain, try using a metal hanger instead.

Use baking soda and vinegar: You can also clear a clogged sink by pouring baking soda and vinegar into the drain. Put a funnel over your drain, and pour in enough baking soda or vinegar to fill up about half of it. Then wait for a few minutes before adding boiling water.

Let this mixture sit for 15 minutes, the longer it sits, the better chance of getting those gunk particles inside getting flushed out. Then run some hot water down into whatever area needs cleaning so everything gets rinsed.

Reason #3: Garbage disposal issues blockage or plug

Garbage disposals are one of the most useful appliances in your kitchen. However, they can also cause problems if not cared for properly.

If your garbage disposal is not working, it may be due to a blockage or plug. Signs of a blockage include:

  • A loud noise comes from the unit when turned on.
  • A strong smell comes from under your sink after running water through it for several minutes.

It’s important to inspect the sink drains for any debris or objects that could be causing a clog. You should also check for any obvious debris, such as hair, lint, or other fluff that might have fallen into your drainage system.

Quick solution

When you are dealing with a garbage disposal issue, remember that fixing it is a simple task and one that can be done in a few minutes.

Clogged Garbage Disposal?

If you’ve recently experienced clogged garbage disposal, it might be time to consider replacing your appliance. Garbage disposals are designed to grind up food scraps, but they can also become clogged by grease or other materials that get stuck in their blades.

To unclog garbage disposal

Unplug the power cord from the wall outlet and remove any items that could block its opening such as plastic bags. Turn on your sink’s faucet so that water flows through the drain pipe until there’s enough pressure for all of its contents to exit into another container. This will help push any debris out of sight.

Reason #4: Dishwasher Blockage, Drain Hose, Drain Hose Loop

When your dishwasher is blocked, you’ll notice the water flowing down out of its drain hose loop. If the hole that connects to your sink or tub isn’t big enough to accommodate what comes out of the dishwasher. There’s a good chance it’ll back up in your home’s pipes and cause major issues with flooding.

Why should you use a drain hose loop?

The dishwasher drain hose loop is a small piece of tubing that connects the output pipe from the dishwasher to your sink. It allows you to run water directly into your garbage disposal without having to worry about clogging it up with food particles!

A drain hose loop is a plumbing feature that prevents the buildup of water and dirt in your dishwasher’s drain. It can also prevent damage to your dishwasher and flooding, which is why it’s important to use one if you have one installed in your home.

When you’re using a drain hose loop, all water drains into this opening before entering into any other part of your home plumbing system including any sinks or tubs. This helps keep dirt from building up inside your machine. 

How to check if the dishwasher drain hose is blocked?

  • Check the dishwasher drain hose. If you have a blockage, it will be evident in the dishwasher itself. You can easily check for this by turning it on and watching for water to stream out of your dishwasher’s drain hose as it drains down into its base.
  • Check the drain hose loop (if applicable) for kinks or bends that may be causing a blockage.”

How to fix a dishwasher drain hose loop to prevent drain blockage?

Luckily, there are plenty of tricks for fixing a blocked drain hose loop in less than an hour without having to call an expensive plumber.

If your dishwasher is draining slowly and you have a drain hose loop, then it’s time to replace it. A clogged dishwasher drain hose will cause the water to back up in your sink or tub while washing dishes and cause an overflow of dirty water.

Reason #5: Air Gap Blockage

An air gap is a plumbing device that prevents the backflow of sewage and cross-connection between two water systems. It can be installed on your home’s main line, or it can be installed at the meter box outside your home.

If your dishwasher is not draining properly and you have a clogged drain, then it’s time to check the air gap. The air gap can be opened by removing the screws that hold down your dishwasher’s trim cover panel. Once you remove this panel, disconnecting any electrical connections will make things easier when working on your machine.

Once you have disconnected everything from the front of your appliance. Take a look inside at where these cables go into their respective holes. If there are any cracks or gaps in these areas then they could be causing problems with water flow through them.

Replacing the Air Gap

  • Remove the old air gap by removing the socket and cap.
  • Install a new one by sliding it over the nipple until it clicks into place. Then tighten down with a socket wrench or pliers.
  • Test your air gap by putting your hand into it. if you feel airflow, all is well. If not, check for debris in there; if so, clean it out with compressed air or an open-flame torch. 

Preventative Care

The kitchen sink is where a lot of things go down. It’s where you wash dishes and clean up after a meal. But it can also be the place where water gets backed up and starts to overflow into your cabinets or floor. If this happens often enough, then your sink will start looking like Niagara Falls. Luckily for us all, there are ways that we can prevent this from happening so we don’t have to hire an expensive plumber:

Clearing the sink trap of debris – If you have a clogged sink or drain, it’s important to check for any debris that may be in your trap. And clear them before taking any action.

Make sure water is draining properly – Check to make sure there are no leaks around the faucet or drainage pipe by turning on the water and watching how quickly it drains into a pan below your sink.

  • Make sure the sink is not clogged.
  • Make sure the drain is not clogged.
  • Make sure the sink is not overflowing. And if it is, empty out any excess water before continuing with this step

Cleaning out your pipes regularly so they don’t build up gunk over time and cause problems later down the line.


You now know the reason why your sink fills up when you run the dishwasher and how to fix them. If you still have problems, there are other options available to you. If the clogged air gap is causing your problem, we recommend calling a plumber who can clean out the drain line for you. You may also want to consider buying an extra sink strainer so that it will be easier for them to fix any future problems with clogs.

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