Well Pump Pressure Switch: Problems, Adjustment, 40/60 Settings, and Replacement
Last updated Reviewed by Sean Mihelich, founder of Save My Well
A well pump pressure switch starts the pump at the cut-in pressure and stops it at the cut-out, most often 30/50 or 40/60. A failing switch shows as a pump that will not start, will not stop, or chatters. Replacement usually costs $100 to $300. The switch carries 240 volts, so turn the breaker off before you open it.
How does a well pressure switch work?
The switch sits on a short pipe near the bottom of the pressure tank. Nebraska Extension's NebGuide G2153 (2012) explains it: when the pressure falls to a set point, often 30 or 40 psi, the switch tells the pump to start. The pump fills the tank until the stop pressure, usually about 20 psi higher, often 50 or 60 psi. A diaphragm under the switch feels the water pressure and opens or closes a set of contacts that carry the pump's power. Systems with a constant-pressure controller use a sensor in a separate unit instead.
The tank and the switch work as a pair. Both Square D's data bulletin 9013DB0701 (December 2007) and NebGuide G2153 say the tank's air charge, read with the tank drained, should be 2 psi below the cut-in: 28 psi for a 30/50 switch, 38 psi for a 40/60 switch.
Safety first: the switch carries 240 volts
DrillerDB's troubleshooting guide (updated July 2026) says pump power is lethal and testing a switch live is pro-only work. A homeowner may look at the contacts and run a continuity test only with the breaker off and the power confirmed dead with a non-contact tester. NebGuide G2153 is stricter: it says homeowners should not attempt to adjust the pressure switch, because it is connected to electric power, and that a licensed professional should do any work on it. If you are not sure, stop and call a well pro or a licensed electrician.
Signs of pressure switch problems
| What you notice | Likely cause |
|---|---|
| Pump will not start, gauge below cut-in, breaker on | Burned or open contacts, or a plugged line under the switch |
| Pump will not stop at cut-out | A jammed switch, or a sensing port clogged with iron sediment |
| Switch clicks on and off every few seconds | Usually a waterlogged tank, not the switch |
| Contacts look black, pitted, or burned | Wear, insects between the contacts, or a pump too big for the switch |
| Water leaks at the bottom of the switch | A damaged diaphragm |
The causes come from the Square D bulletin's troubleshooting table and DrillerDB. Two of them are easy to miss. First, a switch can be fine while the short pipe under it is plugged with calcium or iron, so it never feels the real tank pressure. Second, rapid clicking is usually the tank, not the switch: see our well pump short cycling guide before you buy a switch. Square D also says not to sand, file, or clean pitted contacts with chemicals. Worn contacts mean a new contact kit or a new switch.
How is a pressure switch adjusted?
This is how the Square D bulletin describes adjusting its 9013F and 9013G switches, the common gray switch on many wells. Read it to understand what a pro does, and keep NebGuide G2153's warning in mind.
- Watch the gauge through one cycle and note where the pump turns on and off.
- Turn off the power at the breaker and remove the cover.
- To move both numbers together, turn the large range nut with a 3/8 inch nut driver: clockwise raises cut-in and cut-out by the same amount, counterclockwise lowers them.
- To change only the cut-out, turn the small differential nut: clockwise raises the cut-out, counterclockwise lowers it. The cut-in stays the same.
- Reset the tank air charge to 2 psi below the new cut-in, with the power off and the tank drained.
- Replace the cover, restore power, run a faucet until the pump starts, close it, and watch where the pump stops. Repeat until it is right.
Changing a 30/50 switch to 40/60
The Square D bulletin's table says three and a half turns of the range nut clockwise moves a switch from 30/50 to 40/60, and 8 to 8 and a half turns moves it from 20/40 to 40/60. Two checks come first. The tank air charge must go up to 38 psi. And the pump must be able to reach 60 psi: DrillerDB notes that a sediment-worn impeller may no longer push to a 50 or 60 psi cut-out, and a pump that cannot reach cut-out runs nonstop. If your pump is old, ask a well pro before you raise the setting.
Pressure switch replacement
A new switch is one of the cheaper well repairs, and the pump stays in the well. The Well Guide (updated October 2026) puts it at $100 to $300, and DrillerDB gives $120 to $175, a $25 to $50 part plus wiring and setting labor. Buy the same setting and type as the old switch, including a low-pressure cutoff if the old one had it. The job means disconnecting and reconnecting 240-volt wiring, so have a well pro or a licensed electrician do it. While the switch is off, the pro should clean or replace the short pipe it sits on.
What about a pressure switch wiring diagram?
Each switch has its own terminal layout, printed in its instructions and often inside the cover, and two-wire and three-wire pumps connect differently. A diagram copied from another switch can be wrong for yours. Wiring mistakes on a pump circuit can start a fire or kill, so this is the step to hand to a licensed pro. Note the old wires before anything is disconnected, so the pro can see how your system was set up.
Get help from a local well pro
Most pump problems need a pro to pull the pump. A local well pro can check the pump, the pressure tank, and the switch.
Water also smells or stains? Treat it yourself.
Not the switch?
If the switch checks out, the trouble is elsewhere in the system. Our well pump repair guide works through the breaker, tank, control box, and pump in order, with 2026 costs. Pressure that fades over months with slime in the toilet tank is a water problem, covered in our low water pressure guide.
Straight answers
What does a well pump pressure switch do?
It starts and stops the pump. When the pressure in the tank falls to the cut-in setting, often 30 or 40 psi, the switch closes and the pump runs. When the pressure reaches the cut-out, usually about 20 psi higher, the switch opens and the pump stops. Nebraska Extension's NebGuide G2153 (2012) describes it as the control unit for the system.
How do I know if my well pressure switch is bad?
Common signs are a pump that will not start while the gauge reads below cut-in, a pump that will not stop at cut-out, rapid clicking or chatter, and burned or pitted contacts. Square D's bulletin also lists a plugged line under the switch, which keeps it from reading the tank pressure. Rule out a tripped breaker and a waterlogged tank first.
What does 40/60 mean on a pressure switch?
The pump starts at 40 psi and stops at 60 psi. A 30/50 switch starts at 30 and stops at 50. The pressure tank's air charge, measured with the tank drained, should be 2 psi below the cut-in: 38 psi for a 40/60 switch and 28 psi for a 30/50 switch, according to both Square D and Nebraska Extension.
How do you adjust a well pump pressure switch?
On a Square D 9013F or 9013G switch, with the power off and the cover removed, the large range nut raises or lowers both cut-in and cut-out together, and the small differential nut raises or lowers the cut-out alone. Square D says three and a half turns of the range nut clockwise moves a 30/50 switch to 40/60. Nebraska Extension tells homeowners not to adjust the switch and to use a licensed professional.
Can I change my well pump from 30/50 to 40/60?
The switch can be moved, but the pump must be able to reach the new cut-out. DrillerDB notes that a worn impeller may no longer push to a 50 or 60 psi cut-out, and a pump that cannot reach cut-out runs nonstop. Reset the tank air charge to the new cut-in minus 2 psi. A well pro can check whether the pump has the headroom.
How much does it cost to replace a well pressure switch?
The Well Guide (October 2026) puts a pressure switch replacement at $100 to $300. DrillerDB (2026) gives $120 to $175, a $25 to $50 part plus wiring and setting labor. The pump stays in the well for this repair.
Keep reading
Not sure which fix you need? See every well water treatment, matched to its problem.
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