dishwasher backing up into sink

Having a broken dishwasher is always a hassle that ranges from having to do your dishes by hand to backing up so much it leaks onto your floor. If you notice water backing up into your sink then you know that you’re going to have to take action soon if you don’t want the situation to get worse.

Because the dishwasher and the sink both flow into the same drain line there are several reasons why your dishwasher may be causing your sink to back up. Below, we are going to propose some reasons why your dishwasher is causing backup in your sink and what you can to rectify the problem before you spend money calling a professional out.

The Garbage Disposal

Why Does This Happen?

As mentioned before, both the sink and dishwasher drain through the same line. Because of this, if your garbage disposal is full it can create a blockage that doesn’t allow the water to drain and can back up into the sink.

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How Can I Fix It?

This is one of the simplest fixes we will go over. All you have to do is make sure your garbage disposal is clear which you can do by running the blades or removing the blockage yourself if it’s too big for the blades to cut up. If this is the case you’re going to want to turn off the breaker to the disposal and remove the clog which can be done with needle-nose pliers. It’s always a risk to put your hand in a disposal for fear of it getting stuck so try to use pliers instead. If your garbage disposal is broken then that’s another fix altogether that you will have to take care of first before being able to drain your sink.

Drain Clogs

Why Does This Happen?

Sometimes things go down the drain and block the water from being able to drain properly. This can happen with food that is difficult to dissolve and clump together in the drain or if an unintentional item (like a child’s toy) gets put down the drain.

How Can I Fix It?

Sink cleaner is one of the simplest solutions to this problem. Obviously, it won’t work on a toy but if you need help breaking down food in the drain then getting a quality drain cleaner (view on Amazon) will be one of the best solutions. All you have to do is pour it into the drain, letting it sit for roughly thirty minutes, then run the water to see if the clog has been dissolved. As a last result you may have to use a drain snake if the clog is too far down or if maybe a child did toss a rubber ball down the drain. A drain snake can be fed through the pipe and grab the obstructing object and retrieve it.

The Air Gap

Why Does This Happen?

A lot of kitchens have an air gap which you will find installed by the faucet next to the sink, usually somewhere on the counter. The point of an air gap is to prevent water from backing up, however, the air gap can end up with buildup of its own and can prevent proper drainage.

How Can I Fix It?

Thankfully, it’s not too difficult to clean an air gap. You need to remove the cover on the outside then remove the inner protective cap. Use a flashlight to look inside the air gap and see if you can find any obvious blockages then you can use needle-nose pliers to remove the debris. If you can tell that there is a clog but it’s too far down for you to reach then you can use a bottle brush (view on Amazon) to clean the air gap out.


Why Does This Happen?

Most dishwashers have filters which are meant to catch the scraps of food from your plates when they’re being cleaned. Generally, to find the filter you want to look on the floor of your appliance under the bottom rack which you should remove before proceeding. If your filters get too dirty or clogged then the water won’t be able to pass through and may back up into the sink.

How Can I Fix It?

All machines are different so you should refer to your users’ manual or manufacturers’ website to find your specific model but here are the general steps to cleaning your filters. Most filters have two parts; a screen and a basket/canister. When you remove the filter from your machine cleaning is simple, usually you just need to wash it with warm water and dishwasher soap (if there is still debris attached you may need a rag or brush to unclog it).

Drain Hose

Why Does This Happen?

All dishwashers have a drain hose that is supposed to filter out the water. However, there is a chance of the hose becoming obstructed and you will need to flush the drain hose to stop the water from backing up. This is a more complicated problem and will have multiple steps.

How Can I Fix It?

The first thing you’re going to do is turn off the circuit breaker to the dishwasher for safety reasons, don’t work on the drain hose which the power is on. For a dishwasher drain hose you don’t want to use any store decloggers because there is a possibility of residue remaining and splashing up onto your clean dishes which is unhealthy. Instead you can create a mix of vinegar, baking soda, and warm water into the bottom of the dishwasher.

Next, you’re going to want to unscrew or unsnap the lower kick plate under the door (you may also have to unscrew the door to access). If you are able to scoot the washer out from under the counter, do so; if you can’t you will have to disconnect the wire from the electrical box so you can pull the dishwasher out. After that, you need to disconnect the drain hose from the washer and from under the sink. You may need a bucket or bowl to drain any excess water from the hose into.

Double-check the hose isn’t crimped or broken which can cause a blockage, if you can straighten out a kink that’s great but if it’s damaged then you will need to replace the hose. If there is a clog inside you can try to work the clog out from the outside or you can spray a garden hose into the hose to move the blockage out. When your hose is free and clear you can reconnect the hose clamps and water supply and return the dishwasher to its spot. Try a test run to see if the water flows properly now and make sure there are no other problems that need to be addressed.

You Need to Know This About Your Dishwasher!

If you’re noticing problems with your dishwasher, you need to know what’s causing the issue and if you’ll need to get the dishwasher repaired or replaced. Having a working dishwasher is crucial for any home, and fixing it is just one form of home improvement, but there are many more.

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