We had a new well pump bladder tank and pressure switch installed in July to August. The water pressure switch is kicking on at about 22psi instead of 28psi, the off is still 50psi. Emptied the tank - pre charge is 28 psi as it should be. The switch worked properly at first. How do we fix the low water pressure? Thanks

  • "Emptied the tank - pre charge is 28 psi as it should be?" Are you asking us if the precharge is 28 PSI, if that's as is should be, or are you telling us that this portion seems OK? Please edit your question to clarify
    – FreeMan
    Commented Dec 7, 2021 at 17:01
  • Pre-charge should be 2-3 PSI below cut-in. So if cut-in is 30, 27-28 PSI is right. I would expect you to have issues with the pressure dropping preciptiously at cut-in if the precharge is 28 while cut-in is 22 - the tank is empty at 28, so there's no reserve from 28-22 and the drop would be "gradual" from 50-28, then very sudden from 28-22, watching the gauge as water is used.
    – Ecnerwal
    Commented Dec 7, 2021 at 17:25

1 Answer 1


Since this appears to have either "self-adjusted" out of range or failed in less than 6 months, you might start with contacting your installer to see if the item is under warranty.

Most are adjustable. Turn off the pump breaker: the adjustments are very near the exposed (when you have the cover off to make the adjustments) terminals which have 240V on them, typically, so it's important for your safety to ensure that that is turned off before removing the cover.

Adjust as per the instructions for your model. If the document is not attached to the wall near the pressure switch or included in your pump paperwork packet stored somewhere you can find, look it up on the internet.

Depending on the switch model, there may be one or two nuts on threaded rods backed by springs. If there's one, you only have one adjustment you can make - pressure is increased by going clockwise (normally, in all the ones I have used.) The differential in that case is normally fixed. When you have two, one affects the cut-out, and the other affects the differential (how far between cut-out and cut-in.)

Very few are completely non-adjustable, though they are commonly sold "preset" to a certain pressure and differential. Replacement would be the only option if yours is actually not adjustable.

Test after adjustment, and remember to turn the power off again before re-adjusting.

A (usually small) additional possibility is that of an inaccurate pressure gauge. More commonly they are fine and close enough to accurate until they are obviously broken and unresponsive.

  • We adjusted the pressure switch back to 30/50, within a day it has drifted apart to 24/50. Any ideas what is causing the wider gap, with lower cut in psi?
    – Rebecca
    Commented Dec 10, 2021 at 19:02
  • Sounds like it's a defective pressure switch. Refer to the first sentence of the answer.
    – Ecnerwal
    Commented Dec 18, 2021 at 15:10

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