How Much Water Pressure Does a Dishwasher?

If your dishwasher is not functioning properly or your dishes are not getting cleaned even when you rinse them before placing them in the dishwasher, then it means that your water pressure is inadequate. If the water pressure is less than 20 psi then it may cause water supply valve failure and prevent the water supply valve from shutting. You do not need to call a repairer to fix the issue. Just adjust the pressure switch with the help of household tools that regulate the nozzle pressure coming from the dishwasher’s jet.

How Much Water Pressure Does A Dishwasher Need?

If your dishwasher is unable to remove food particles or even soap from the dishes, make sure the water supply in your kitchen meets your dishwasher’s requirements of water pressure and water temperature. The principal method of cleaning your dishes in the dishwasher is completely based on water pressure and water temperature. 

The water pressure must be between 20 PSI and 120 PSI (pounds per square inch).

Reasons For Low Water Pressure

woman setting dishes
  • Inside your dishwasher, the water inlet is probably the culprit; it may not be working properly. You can use a multi-meter to test it. does not matter if the dishwasher is old or new.
  • Check under the sink for a kinked or restricted water line or hose, to make sure that there is nothing else that could be causing the low water issue.
  • Set the dishwasher to run a wash cycle. Let it fill with water and when it starts the cycle, check the water level. It should be under the heating components. If the water level is not below the heating component then fill a small pot with water and fill the dishwasher water level manually to below the heating components. Now close the door of the dishwasher and let it work, If water is getting to the top rack then there is enough water for your dishwasher
  • There may be a clog in your water inlet fill valve or water fill line. This line supplies water to your dishwasher. Remove the line where it attaches to the fill valve. Make sure nothing is clogging the screen on the inlet fill valve. Also, check the water fill line for blockage.
  • The fill water may be draining out of the dishwasher by going straight out the drain hose. Check if your drain hose is not placed straight. There must be a loop on it.
  • Turn off the water “shut-off valve” under your sink when you install your dishwasher. The water “shut-off valve” may not be working properly because of blockage. Make sure that the “shut-off valve” is open fully and not clogged.

Important Requirements

There are some important requirements that you should consider before purchasing and installing your dishwasher to avoid any errors.

Water Pressure

The water supply pressure should be between 20 psi and 120 psi( pounds per square inch).

Caution: Water pressure less than 20 psi will cause water supply valve failure and prevent the water supply valve from shutting due to water temperature.

Water Temperature

For best cleaning performance the required water temperature is between 120- 149° and if it is not accordant, you may experience several errors with your dishwasher.


It is used to connect the water line to the dishwasher. Mostly, 90-degree elbow does not come with the dishwashers but you can purchase it.

Supply Line

Usually, the water supply lines possess a length of 10 feet. Most plumbing stores sell water supplies of the same size. A stainless steel supply line is recommended. 

What Is The Function Of A Pressure Switch In A Dishwasher?

As the washer fills with water, it enters the tube from the bottom and increases pressure in the airspace within the tube. The switch shuts off water flow to the tub when the pressure reaches the critical point.

How To Adjust The Pressure Switch On The Dishwasher?

There are a few easy tips that will help you to adjust the pressure switch on the dishwasher

How Much Water Pressure Does a Dishwasher Need?
  1. First of all, turn off all the sources of water and electricity. Twist the faucet handle as much as possible to turn off the water and check by turning on the water in the sink. Disconnect the electric cord by pulling the dishwasher out. You can also cut the source of electricity by throwing the switch to the kitchen in your breaker box.
  2. There is an access panel on the back of your dishwasher. First, pull it out from the wall and remove it.
  3. Find the water heater. It looks like a long tube with a control box attached to it. The pressure switch is a round pipe that threads directly into the heater tube itself.
  4. Adjust screw by using a flat-bladed screwdriver. Reduce the pressure on the dishwasher nozzle by turning it clockwise; turn it counterclockwise to increase the pressure to the nozzles but be careful not to unscrew it too much, or there may be a leakage in the future.
  5. Once you are done with adjusting the switch, put the cap back and screw the access panel back into place. Now, you are good to give your adjusted dishwasher a try.

Tips For Reducing Leaks And Water Damage

There are a couple of things that you can do to reduce the risks of leaks and water damage after installing your dishwasher

  • When your dishwasher is not going to be used for a week or longer shut off the valve.
  • Regularly, check for leaks where the hose connects to the water supply shut-off valve.


The water pressure must be between 20 and 120 psi ( pounds per square inch). Water pressure less than 20 psi may cause water supply valve failure. Sometimes, inlet water pressure gets reduced due to blockage in pipelines, or the strainer installed in the hose is clogged. Insufficient water in the dishwasher can also cause poor cleaning. The dishwasher will not fill with water if the float gets stuck in the raised position. In conclusion, to check if your dishwasher is getting enough water or not start a frequent wash cycle.