I have a submersible pump. When the water pressure reaches 30 it clicks on. Pressure builds to 50 and then clicks off. Just as it should. Then just when it clicks off, the pressure will drop and surge back a few time before settling at about 45 pounds or so. But what happens is when it drops fast after the pump shuts off, it will drop below 30 pounds for a second. This clicks the pump back on. It runs a few seconds and then shuts off. Then it surges/drops pressure and then turns back on again. My pressure tank as 28 pounds pressure when all water is discharged. I can't think of what could be wrong.

Thanks in advance for the help.

Dave

Do you a shut off valve to allow you to turn off water going to the house?

Does the system hold pressure when no water is being used?

Yes it holds pressure when the house is turned off. The pressure tank is in the basement about 30 feet from the well. Not sure if that matters. Fairly typical around here.

Is there a checkvalve between the tank and the wellhead?

When the house is cutoff, does the "rebound" still happen? In other words, if you let the pump cut on, and then turn the house off before the pump cuts off, does the rebound still happen? If so, then it sounds like the tank is "bouncing" pressure up and down the well pipe. I would think a check vaLVE in just before the pressure tank would stop that.

I will try that and see, but I will bet it still happens. It does act like the tank is bouncing pressure up and down. I don't understand where you are putting the check valve. If I put it in front of the tank, then water could get into the pressure tank but not out. The line right now comes out of the well, then the pressure switch. This is in a well house. Then about 30 feet to the house where the pressure tank is and on to the rest of the house.
Thanks

Ideally, the switch should be next to the tank, not 30' away. The checkvalve would in your house, where the pipe from the well goes into the tank. This will allow water to enter the tank, but not allow it to "pulse" back towards the well.

Where is your pressure gauge, by the tank, or by the switch?

Take a look at this thread. Note how it was resolved. (The man intended to say he had to move the tank closer to the switch.)

https://www.askmehelpdesk.com/plumbing/moved-well-tank-now-pressure-builds-up-too-high-trips-relief-valve-567729.html

Maybe that is the problem. The well and pressure switch are in the pumphouse about 30 to 40 feet from the house, and the pressure tank is inside the basement. I will take a look and see if the pressure tank will fit in the wellhouse and let you know.

Personally, I'd try a checkvalve first, as it is the most simple alternative. 15 bucks and an hour or two of time.

Please do let us know how this problem is resolved. Best wishes.

What I ended up doing was I just put a 2 gallon pressure tank right at the well where the presseure switch is. I left my 30 gallon tank in the basement. The 2 gallon tank in the well house totally fixed the problem. Pump shuts off at 50 pounds and no bouncing up and down.

Thanks for the help.

Glad it worked out for you. This is one to remember.