How to Adjust the Pressure Switch on a Well Pump

From a slow trickle to a hose jet stream, the wrong water pressure can take the comfort out of your shower. Fortunately, adjusting the pressure switch on your well pump is a quick and easy skill to learn that can bring peace back to your shower time. Whether you’re turning up or toning down, this guide will walk you through the steps to get your pressure switch set just right.

Calling in a professional to adjust the pressure can cost between $100 to $150 for a house call, whereas adjusting it on your own only requires a wrench.

Why Do I Need to Adjust My Well Pump’s Pressure Switch?

If you have a non-automatic switch, you might need to adjust it to get the right level of water pressure in your faucets, sinks, showers, and other water fixtures. Even if you have an automatic switch, you can adjust it to change the pressure to something you find more comfortable.

How to Adjust the Pressure Switch

Once you’ve grabbed your wrench, you can follow these steps to adjust your well pump’s pressure switch.

1. Turn Off the Power Breaker

Always start by disconnecting the power to your pressure switch before you make any adjustments. Your pressure switch power supply can usually be found on your main power breaker, sometimes under a label like “well pump” or “water pump.”

If you’re not sure which switch connects to your well system, give your local electrician a quick call—it never pays to take risks when you’re working with electricity.

2. Remove Your Pressure Switch Cover

The pressure switch cover is typically a small plastic cube, usually gray or black in color. It’s often held in place by a nut that you can untwist by hand or with a wrench.

Inside the cover, you’ll find a guide to your pressure switch’s factory settings. This can also include important details like upper and lower pressure limits.

3. Identify Cut-In and Cut-Out Settings

Well pump pressure switches include two settings: cut-in and cut-out. Cut-in pressure is the low-pressure point where your well pump starts, while cut-out pressure is the high point that turns off the pump.

There’s a range between these two points, called the differential. For example, it could go from 30 to 50 PSI (pounds per square inch). The standard differential is 20 PSI. Lowering the cut-in point reduces your water pressure, say from 30 to 50 PSI to 20 to 40 PSI, whereas raising it will give you a more forceful pressure.

You’ll usually find two nuts inside your pressure switch: a large center nut and a small nut above or below. It’s always a good idea to look at the inside of the cover to check which is which, but on most systems, the larger center nut controls cut-in and cut-out pressure.

4. Turn the Cut-In/Cut-Out Nut to Adjust the Pressure

Turning the large center nut will adjust both your cut-in and cut-out pressure, lowering or raising the overall pressure. You’ll still have the same differential (normally about 20 PSI).

Measure and record the nut position before you make any adjustments. This can help you track how many PSI you’ve adjusted and return to the factory settings if you ever want to reset your pressure switch.

To lower your pressure, turn the nut counterclockwise. To raise it, turn the nut clockwise. As a general rule, one full turn of the nut will change your pressure by about 2 to 3 PSI.

5. (Optional) Adjust the Pressure Differential

The second nut on your pressure switch changes the differential—for example, you could go from 30 to 50 PSI to 30 to 45 PSI. This is rarely used, and you won’t need it if you only want to raise or lower your water pressure.

Changing the differential can also prevent your pump from properly turning off, and can ultimately shorten the lifespan leading to a costly well pump replacement or pump repair. It’s generally not advisable to turn this nut unless you have a specific need, like if the previous owner had set the differential to something other than 20 PSI. 

6. Test Your Pressure

Once you’ve adjusted your pressure switch, replace the switch cover and turn the power back on. When the pump turns on, record the low PSI and then record the high PSI again when the pump turns off. This will show you your new cut-in and cut-out pressures.

It can sometimes take a few tries to get the pressure where you want it, but it’s always a good idea to start slow and then adjust more later. If you need to make any adjustments, remember to turn off the power before you start.

If you’re finding that even after a few tries you still can’t get the pressure to change, it may be a sign that it’s time for a new well pump.

DIY vs. Hiring a Pro for Well Pump Adjustments

Adjusting the pressure switch on a well pump takes less than half an hour and only requires a wrench, which makes it an approachable DIY task. However, to do this safely, you’ll need to switch your electricity on and off. If you aren’t comfortable with this, it’s better to call a professional to adjust your well pump’s pressure switch.

How to Fix Common Well Pump Pressure Switch Problems

If you’re dealing with consistently low water pressure, a pump that switches on and off quickly, or a pump that won’t turn on or off, there might be a problem with your well pump pressure switch. Before calling a pro, you may be able to fix the issue with one of these troubleshooting tips:

• Look for leaks: Sometimes, water can seep into the switch housing. If you notice any water in this area, cut the power immediately and call a pro to replace the switch. Otherwise, if the leak is near the plumbing connection, you may be able to tighten it yourself. 

• Clear the pressure sensor: With the power turned off, clear out any sediment or other debris in the tube that connects the switch to the water supply. 

• Test the water pump cycle: When the switch’s internal spring gets loose, it can prevent the switch from working. You can test this by opening a faucet and allowing the pump to complete a full cycle. If the switch fails to turn on, you might have a spring issue.