Sink Backs Up When Dishwasher Runs

If your sink backs up when the dishwasher runs, it can be a frustrating and messy problem. There are several potential causes for this issue, and the solution will vary depending on the underlying cause. Here are some of the most common reasons why your sink may be backing up when the dishwasher is running, along with steps you can take to fix the problem.

Clogged Drain Line

One of the most common reasons for a sink to back up when the dishwasher runs is a clogged drain line. The drain line is the pipe that carries wastewater from the dishwasher to the main drain. If this line becomes clogged, it can prevent the water from draining properly and cause it to back up into the sink.

To fix a clogged drain line, you can try using a drain snake to clear the clog. You can also try pouring a mixture of baking soda and vinegar down the drain, which can help to dissolve clogs.

Blocked Air Gap

Another common cause of a sink backing up when the dishwasher runs is a blocked air gap. An air gap is a small device that is installed between the dishwasher and the drain line. The purpose of an air gap is to prevent wastewater from flowing back into the dishwasher. If the air gap becomes blocked, it can create a vacuum that prevents the water from draining properly.

To fix a blocked air gap, you can try cleaning it with a toothbrush or a pipe cleaner. You can also try pouring a mixture of baking soda and vinegar into the air gap, which can help to dissolve any clogs.

Defective Dishwasher Drain Pump

In some cases, a sink may back up when the dishwasher runs due to a defective dishwasher drain pump. The drain pump is responsible for pumping the wastewater out of the dishwasher. If the drain pump is not working properly, it can prevent the water from draining properly and cause it to back up into the sink.

To fix a defective dishwasher drain pump, you will need to replace the pump. This is a relatively simple repair that can be done by most homeowners.

Overloaded Dishwasher

If your sink backs up when the dishwasher runs, it is possible that you are overloading the dishwasher. When the dishwasher is overloaded, it can prevent the water from draining properly and cause it to back up into the sink.

To avoid overloading the dishwasher, make sure to only wash full loads of dishes. You should also avoid putting large or bulky items in the dishwasher.

Incorrectly Installed Dishwasher

In some cases, a sink may back up when the dishwasher runs due to an incorrectly installed dishwasher. If the dishwasher is not installed properly, it can prevent the water from draining properly and cause it to back up into the sink.

To fix an incorrectly installed dishwasher, you will need to have a qualified technician reinstall the dishwasher.