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When to Adjust a Pressure Switch


The following are a few examples of when you may consider adjusting your pressure switch:

  • Pump is located at a lower elevation then the home and current setting is not providing sufficient pressure
  • Insufficient pressure at the faucets, shower, hose bib, etc.
  • Sprinkler heads require higher pressure than the switch is set to
  • Pump is not able to build up enough pressure to reach current cut-off setting

It is worth noting that we regularly get calls to customer service from individuals that have tried adjusting their pressure switch after noticing a change in water pressure. It is probably the easiest component to adjust, however, it is usually not the first thing that should be looked at. I will not be addressing troubleshooting low water pressure in this blog, I just want to emphasize that the pressure switch is almost never the problem if you have a drop in pressure.

The information below is from one of our most popular blogs titled How to Adjust a Pressure Switch (posted May of 2018) with a few updates. Also, the R.C. Worst YouTube Video: How To Adjust a Pressure Switch was published in July of 2017.

The starting and stopping of a well water pump is typically controlled by a pressure switch similar to the one shown below. The switch is preset with both the cut-on and cut-off pressures known as the range. They normally come in three different ranges: 20 to 40, 30 to 50, and 40 to 60 PSI. The cut-on pressure is the low pressure setting that starts the pump and the cut-off pressure is the high pressure setting that turns off the pump. For example, a 30/50 switch will turn on the pump when system pressure reaches 30 PSI and turn it off when the pressure reaches 50 PSI. Adjusting the range can be done by following a few simple steps.

Caution! Electricity can be very dangerous, especially if you are inexperienced. Always use caution when working with electricity and turn off the power supply/circuit breakers when testing components or making any adjustments within the electrical system. If you are not 100% confident you can perform any of these tests safely, call a professional.

Remove the cover on your pressure switch. Factory presets can be found inside the cover of the pressure switch (as shown on right above). To increase or lower both cut-on and cut-off pressure you will turn the nut on top of the large center spring as seen in the picture below. You will turn the nut counterclockwise to lower both cut-on and cut-off pressure or turn the nut clockwise to raise both cut-on and cut-off pressure.

Important note: If you adjust your cut-on pressure you will also need to adjust the pressure tank air charge. The pressure tank should be set at 2 PSI less than the cut-on pressure. Click here to see a video: How to Check and Adjust Pressure Tanks or click here to read the blog: How to Check and Adjust Your Pressure Tank


If your switch has a second, smaller spring then you also have the ability to adjust the differential. Adjusting the differential will only adjust the cut-off pressure. There are very few applications where you should adjust the differential. Turn the differential nut counterclockwise to lower cut-off pressure or turn the nut clockwise to raise cut-off pressure.

If your pressure switch is not working like it was previously, it is also important to check for other causes.

  1. Check for sediment/debris in the nipple or pressure tube leading to the switch (shown in center and right photos below).
  2. Check for sediment in pressure switch diaphragm (shown in photo in the left below).
  3. Check for signs of aging metal springs or signs of switch wear/damage caused by temperature changes.


Keep in mind that the Pressure Switch is a key element to a properly working system and they are relatively inexpensive. We recommend replacing them rather than trying to repair them. Click here to purchase a new pressure switch

Click on the hyperlinks below to see pressure switch videos on the RC Worst YouTube channel:

Click here to see How To Adjust a Pressure Switch

Click here to see Square D Pressure Switch

Click here to see Low Water Pressure Cutout Switch | Square D M4 Pressure Switch W/ Low Pressure Cut-Off

If you have further questions about when to adjust your pressure switch or your water system please do not hesitate to call our experts at 855.329.4519.