How to Set the Pressure Switch on a Well

G.K. Bayne

Pressure switches on private home well systems generally come preset from the factory. In most cases the switches are set in a range. The range of the pressure is typically a 20 psi (pounds per square inch) span. The pressure switch is set to turn on the pump when the water pressure is at 30 psi.

The switch will then turn the pump off when the system reaches an upper limit of 50 psi. By removing the plastic cover on the pressure switch you can adjust this range to either a higher or lower setting.

  1. Remove the top plastic cap of the pressure switch. Note that there are two springs with a top adjustment nut. The larger spring and adjustment nut is for the overall range of the pump’s operation. In other words, adjusting this nut clockwise will raise the pump-on and pump-off pressures. The smaller spring and adjustment nut is for raising the overall cutoff pressure of the pump.

  2. Open a nearby faucet to drain water from the plumbing system. This will allow the pump to cycle while you are making the adjustments. Note the water system’s pressure gauge while making the adjustments so the work you perform is accurate.

  3. Use the ½-inch end wrench on the larger spring adjustment nut. Turn the nut in a clockwise direction to increase the overall pressure span. As stated earlier, the typical preset factory span is 30 psi for the pump on and 50 psi for the pump off. Turning the nut in a counterclockwise direction will lower the span accordingly. Observe the pressure gauge. Allow the pump to cycle a couple of times through an off and on operation.

  4. Use the 7/16-inch end wrench to adjust the overall pump off pressure. Turning the nut clockwise will raise the pressure as to when the pump will shut off; turning the nut in a counterclockwise direction will lower the pressure. Attempt to keep the on and off range of pressure around 20 psi. Lowering the cutoff pressure may cause the pump to operate too frequently.


Use caution whenever accessing the electrical pressure switch. Combining water and electricity can result in an electrical shock. Exercise caution whenever turning the smaller spring adjustment nut. Turning the adjustment nut too much in a counterclockwise direction will lower the pump off pressure. This will mean the pump may never shut off and cause premature pump failure.