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How to Increase Water Pressure on a Pump

by Carl Jensen

Plumber, Welder, Contractor

> 2 min read


To increase the pressure on a water pump, you need to adjust the pressure switch. You can do this with simple tools such as a wrench and a screwdriver. In general, you won’t need to handle wiring or complicated electronics. 

Whether it’s a booster pump, a shallow well pump, or jet pump, most of these units work with a pressure switch. The switch will tell the pump to turn on at a specific pressure and turn off at another. 

Before starting, ensure the pump is off by turning off the breaker at the control panel. You can also do this by disconnecting power for the switch or pump.

HERE ARE OTHER QUESTIONS THAT YOU MIGHT HAVE ABOUT WATER:

What is a Pressure Switch?

Most types of water pumps have a small pressure switch. This is usually a gray or black small box located right by the water pump. The plastic cover on the box can have different colors, and it has a white sticker with instructions on it. When you take off the plastic cover, you’ll find some wiring terminals.

How it Works

The switch automatically starts or stops the pump according to preset pressures. Therefore, when there’s a change of pressure in the pipes, the switch automatically notices and adjusts accordingly. 

The cut-on and cut-out points refer to the pressure points where the pump automatically adjusts pressure. The cut-on point is for falling pressure, and the cut-out point is for rising pressure. These points are measured in PSI, or pounds per square inch, and are set with a specific range or differential. 

Most pressure switches have a preset pressure differential of about 20 lbs. You don’t have to keep this preset range, but it usually works well. It’s possible to adjust the cut-in and cut-out points to your liking.

Checking the Pressure Range on Your Pump

To start, check the preset pressure points on your pump. You can find the numbers for the switch on the plastic box inside. Different types of pumps are preset with specific pressure ranges. A submersible pump is commonly set with 40 to 60 cut-in and cut-out points. Other types, such as jet pumps or centrifugal pumps, tend to run on a 20 to 40 differential.

How to Adjust the Pressure

Adjusting a pressure switch isn’t complicated. Since many people aren’t familiar with handling pressure switches or water pumps, it’s essential to follow a few steps when learning how to increase water pressure on a pump. The only tools you need are a screwdriver and a wrench. 

Step 1: Turn off power

The first thing is to turn off the power going to the switch. Do this by disconnecting the wires or cables going to the water pump or switch, or simply turn off the breaker’s power. 

Step 2: Locate the pressure switch and uncover

The pressure switch is a small box right by the water pump. Remove the cover by taking off a small screw outside the box. You can remove the screw by hand. 

Once you have uncovered the pressure switch, you’ll notice four wiring terminals and two springs or pressure adjustment screws. The big one raises or lowers both the cut-on and cut-off points, while the small one only raises or lowers the cut-off point. 

Step 3: Check the instructions on the cover

When learning how to increase water pressure on a pump, the instructions on most switch boxes are helpful. Many pressure switches have a white sticker with instructions right underneath the cover. On the sticker, there’s information about the pressure differential. The instructions might vary from model to model. If your model doesn’t provide much information, you’ll have to experiment with changing pressures. 

The instructions indicate how to screw the nut to raise or lower the pressure on most water pumps. For example, every complete turn of the nut can increase the pressure by about 2½ PSI. Figure out how much you want to change the force and calculate the number of turns. 

Step 4: Increase the pressure

Turn the nut on the large spring clockwise to raise the cut-on and cut-off pressure points. If you want to lower them, turn the nut counterclockwise. So, for example, if the differential on your pump is 40-60 PSI, you can raise it to 50-70 PSI. 

If you don’t have detailed instructions on turning the nut, use the following rule of thumb: one turn on the nut raises 2 to 3 PSI pressure. If you want to increase the cut-on and cut-off points by 10 PSI, you should turn the nut about five times. 

In general, don’t change the smaller nut. This one adjusts the differential, and there are a minimal number of cases where this is necessary. Adjusting the differential means if the differential is 40 to 60, by turning the smaller nut counterclockwise, you change it to 40 to 57. 

Step 5: Adjust the pressure tank 

Many pressure booster systems come with a tank that’s half-full of water and half full of air. Between the two, there’s a diaphragm, and as the water comes in through the top, the air on the bottom gets compressed. When you open a faucet, the tank uses compressed air to pump up the water. The pressure tank should be at least 2 PSI less than the cut-on pressure.


Enjoy the Increased Water Flow in Your Home

A simple way of checking that everything is working correctly is installing a pressure gauge on the pipe leading out from the pressure booster system. After adjusting the pressure, turn the pump back on by flipping the breaker. 

As the water leaves the booster, you should notice the pressure increasing on the gauge. If you set the differential to 40 to 60 PSI, then the indicator should go right up to 60 and then stop. 

Some people have too much water pressure in their homes. In that case, a pressure gauge might show around 120 PSI. An effective way to deal with this problem is by installing a pressure-reducing valve.

Carl Jensen

About the Author

Carl Jensen is a plumber with over 50 years of experience in the industry, as well as related jobs like underwater welding. He runs a successful plumbing practice in Tampa, Florida, and contributes his plumbing expertise to our DIY articles, and helps to fact check and consult on most of our other stuff to boot.