I have a 40 gallon (bladdered) pressure tank in the basement which keeps pressure to my office building, and a 2-inch 2 horsepower submersible pump in a dug well 450 feet away.

The pump is cycling waaay too fast, and the tank will hold pressure at 41 pounds to 43 pounds but not at 60 pounds at shut-off pressure. (The pump comes on at 40 and shuts off at 60). It only takes 6 seconds for the pump to come on and shut off and I fear I will cook the pump if this keeps up.

I have recently tested the pressure in the tank and it is 50 pounds. Does this mean the bladder leaked and caused pressure to increase in the tank? I know the tank pressure should be set at around 39, or a little below the 'turn-on' pressure. Could this be the cause of the short cycle?

  • 50 PSI - under what conditions? If there's 50 PSI of water, the tank will read 50 PSI as well. The important reading is when the tank is completely empty of water and water pressure is at zero. That should be 37-38 PSI for a 40 PSI cut-in.
    – Ecnerwal
    Jul 8, 2017 at 19:20

2 Answers 2


The bladder is there to flatten the pressure/volume curve so pressure doesn't change rapidly as water is pumped.

This allows for a longer duty cycle.

The expected symptom of a burst bladder is just as you describe.

  • 2
    Turn off the pump at the circuit breaker panel. Run a faucet until the water stops (tank now empty),. Check the tank pressure to see if it it set at 39 pounds,if not correct the pressure. Also you could depress the air filler fitting to see if water come out when the pump shuts off indicating a full tank. . You should only get air out.
    – d.george
    Jun 2, 2017 at 16:29
  • D.George this is the best answer so far you should make it so.+
    – Ed Beal
    Sep 18, 2017 at 23:37

It needs air.

Get hold of an air compressor and give it a charge. Be sure to be running water while charging, and the pump is off. Easy.

If you need to do this more than once a year there might be a problem with the bladder.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.