The water pressure switch is typically located near the well tank. Before removing the switch, make sure the power is off, then take off its cover and disconnect the wiring.

If the Switch is Bad, Replace It If you find the pressure switch is bad, test the pressure tank to make sure it isn't waterlogged (see Problem: Pulsing Water). To replace the switch, start by ...

As water pumps into the tank, its air pressure increases until it reaches a specific, preset level. When it reaches that point, the air pressure will push water through your home’s plumbing system.

When water pressure in the system tank drops below a preset level — typically 30 pounds per square inch (psi) — the pressure switch energizes the pump that then delivers water to the tank.

Using the pressure toggle switch, you can swap the pump power between 30 and 50 PSI, getting you a maximum of 950 gallons per hour with 26 feet of suction lift.