Well Pressure Switch Problems
The pressure switch is the small gray box that tells your well pump when to run. When it fails, the pump may not start, may not stop, or may chatter on and off. Call 417-759-4388 to reach a DNR-permitted contractor near Springfield.
- Pump won’t start
- Pump won’t shut off
- Clicking or chattering
How a well pressure switch works
The switch senses water pressure through a small fitting near the pressure tank. When pressure falls to the cut-in setting, it closes and starts the pump. When pressure rises to the cut-out setting, it opens and stops the pump.
Common residential switches, such as Square D Pumptrol models, are sold in 30/50 and 40/60 psi versions. Some include a low-pressure cutoff that shuts the pump off if pressure drops very low, which can protect a pump when the well runs dry.
The switch and the pressure tank work as a pair. The tank’s air charge is normally set about 2 psi below the switch’s cut-in pressure, so a change to one often affects the other.
Common pressure switch symptoms
These are possibilities, not a diagnosis. Several of them can also be caused by the tank or the pump.
| What you notice | Possible causes |
|---|---|
| Pump won’t start, gauge is below cut-in | Burned or pitted contacts, a clogged pressure-sensing tube, a tripped low-pressure cutoff, or no power reaching the switch |
| Pump won’t shut off | Contacts welded closed, a switch set above what the pump can reach, or a pump that can no longer build pressure |
| Rapid clicking while water runs | Usually a pressure tank that has lost its air charge; sometimes a clogged sensing tube |
| Pump starts and stops on its own | Pressure leaking away through a check valve, plumbing, or a running fixture |
| Buzzing or chattering at the switch | Worn contacts or pressure bouncing at the cut-in point |
| Pump stopped after the well ran low | A low-pressure cutoff switch may have tripped and needs a manual reset once the cause is found |
What a contractor will check
- Voltage at the switch and whether the contacts close and open cleanly
- The sensing tube and fitting for sediment or scale
- Cut-in and cut-out readings on the gauge
- The pressure tank’s air charge
- Whether the pump can actually reach the cut-out pressure
Repair or replace the switch?
Pressure switches are inexpensive compared with most well repairs. When the contacts are burned or the switch is old, replacing it is usually simpler than repairing it. If the switch failed because the pump short cycles, the tank should be checked too, or the new switch may wear out the same way.
Don’t tap, pry, or hold the switch contacts closed to force the pump on. It’s a shock hazard, and running a pump that can’t build pressure can damage it.
Pressure switch FAQ
Can I adjust my well pressure switch myself?
Adjustment means working inside a box with live 240-volt terminals. Raising the settings can also push the pump beyond what it was sized for. Have a qualified contractor make any changes.
Why does my well pressure switch keep clicking?
Rapid clicking while water runs usually means the pressure tank has lost its air charge, so pressure swings quickly between cut-in and cut-out. A clogged sensing tube can cause it too.
What does the lever on the side of my pressure switch do?
Some switches have a low-pressure cutoff lever. If pressure drops very low, the switch shuts off the pump, and the lever is used to restart it. If it trips repeatedly, find out why before resetting it again.
Need help with your well?
Call or send a request. Tell us your town and what the water is doing, and we will connect you with an independent local well and pump contractor.
Ozark Well Pros is an independent referral service, not a well drilling or pump installation contractor. We connect homeowners with independent, Missouri DNR–permitted well and pump contractors, who set their own pricing, schedules, and warranties.