What a pressure switch does and why you might need to adjust it
Your well pump's pressure switch is a small device that turns the pump on when water pressure drops below a set level and turns it off when pressure reaches a higher level. It maintains the pressure range that keeps water flowing steadily through your house. If your water pressure feels weak, the pump cycles on and off too often, or you hear the pump running constantly, the pressure switch may need adjustment.
The switch sits on or near your pressure tank and has two adjustment screws: one controls the cut-in pressure (when the pump starts) and one controls the cut-out pressure (when it stops). Most residential systems are factory-set to cut in at 30 pounds per square inch (psi) and cut out at 50 psi. Adjusting these settings is straightforward, but it requires a pressure gauge and careful attention to the correct sequence.
Key Takeaways
- A pressure switch controls when your pump turns on and off; adjusting it requires a pressure gauge and takes about 15 minutes.
- The cut-in pressure (when pump starts) and cut-out pressure (when pump stops) are set by two separate adjustment screws on the switch.
- Always drain the tank and turn off power before opening the switch cover to avoid injury from pressurized water or electrical shock.
- Most residential systems work best with a 20 psi difference between cut-in and cut-out settings, though your system manual may specify a different range.
- If adjustment does not solve the problem, the switch itself may be faulty and need replacement by a licensed well technician.
Gather your tools and turn off power
You will need a pressure gauge (available at hardware stores for $15–$40), an adjustable wrench or socket set, and a flathead screwdriver. The gauge screws onto a test port on the pressure tank, usually a small brass fitting near the bottom or side of the tank.
Turn off the pump at the breaker or switch before you begin. This prevents the pump from starting unexpectedly while you work. Open a faucet inside the house to release pressure from the tank, then close it once water stops flowing. This step is critical—working on a pressurized tank can cause injury.
Read the current pressure and understand what you are seeing
Screw the pressure gauge onto the test port on the pressure tank. Turn the pump back on and let it run until it shuts off automatically. The pressure reading when the pump stops is your current cut-out pressure. Write this number down.
Turn on a faucet inside the house and let water run until the pump kicks back on. The pressure reading when the pump starts is your cut-in pressure. Write this down as well. The difference between these two numbers is your pressure band. Most systems have a band of 15–20 psi, though some older systems run 10 psi and some newer ones run 25 psi. Your well pump manual will specify the correct band for your equipment.
Locate the adjustment screws and remove the switch cover
Turn off power to the pump again. The pressure switch is a cylindrical or box-shaped device mounted on or near the pressure tank. It has a plastic or metal cover held on by one or two bolts or screws. Remove these fasteners and carefully lift off the cover to expose the adjustment screws inside.
You will see two screws: one larger (usually with a nut) and one smaller. The larger screw adjusts the cut-out pressure (the upper limit). The smaller screw adjusts the cut-in pressure (the lower limit). Some switches label these, but not all—check your pump manual if you are unsure which is which. Do not touch any wiring or electrical components inside the switch.
Adjust the cut-out pressure first
Turn the pump back on and let it run until it shuts off. Check your pressure gauge. If the cut-out pressure is too high (above your target), turn the larger adjustment screw counterclockwise one-quarter turn. If it is too low, turn it clockwise one-quarter turn. Make small adjustments—each quarter turn changes pressure by roughly 2–3 psi.
After each adjustment, turn the pump off, open a faucet to release pressure, then turn the pump back on and let it cycle off again. Check the gauge and repeat until the cut-out pressure matches your target. Once the cut-out is correct, leave that screw alone.
Adjust the cut-in pressure second
The cut-in pressure should be 15–20 psi below the cut-out pressure (or whatever your manual specifies). Turn on a faucet to drop the pressure, and watch the gauge until the pump kicks on. Note the reading. If it is too high, turn the smaller adjustment screw counterclockwise slightly. If it is too low, turn it clockwise.
Again, make quarter-turn adjustments and test after each change. The pump should start reliably at your target cut-in pressure and stop reliably at your target cut-out pressure. Once both are correct, turn off power, close the faucet, and replace the switch cover.
Test the system and know when to call a professional
Turn the pump back on and let it cycle through a full on-off cycle while you watch the gauge. The pressure should rise smoothly from cut-in to cut-out, and the pump should stop cleanly without stuttering or chattering. Water pressure at your faucets should feel normal and steady.
If the pump still cycles too often, pressure feels weak, or the pump will not stop running after adjustment, the switch itself may be worn out or the tank may have lost its air charge. These problems require a licensed well technician. Do not attempt to replace the switch yourself unless you have experience with electrical work—the switch carries live current even when the pump is off.
Frequently Asked Questions
What is the difference between cut-in and cut-out pressure?
Cut-in is the pressure at which the pump turns on; cut-out is the pressure at which it turns off. The difference between them (the pressure band) determines how often the pump cycles. A wider band means the pump runs less often but delivers water at a wider range of pressures. A narrower band means more frequent cycling but steadier pressure.
Can I adjust the pressure switch without a gauge?
No. Without a gauge, you cannot see what pressure you are actually setting, and you risk over-pressurizing the tank or setting pressures too far apart. A pressure gauge costs less than a service call and is worth the investment if you plan to maintain your own well system.
Why does my pump run constantly after I adjusted the switch?
This usually means the cut-out pressure is set too high or the cut-in pressure is set too low, so the pump never reaches the pressure needed to shut off. Turn off power, release pressure, and check your adjustment screws. If they are in the correct position and the pump still runs constantly, the switch or tank may be faulty and needs professional inspection.
Is 30/50 psi the right setting for every well pump?
No. Some systems run at 40/60 psi or other ranges depending on the pump model, tank size, and household demand. Always check your pump manual for the manufacturer's recommended settings. If you no longer have the manual, the model number is usually stamped on the pump housing—you can search online for the manual or call the manufacturer.
How often should I adjust the pressure switch?
Under normal conditions, you should not need to adjust it more than once every few years. If you find yourself adjusting it frequently, the switch is likely wearing out and should be replaced. Frequent adjustment is a sign that the switch contacts are becoming unreliable.