Changed pressure switch and pump would not shut off. Pressure would only build to 40. ( 30/50 system). Adjusted pressure switch and now pump shuts off but low pressure in the house. Leak s checked for all over and found nothing. Bad pump? Or?

Is your pump in the well or above ground?

If above ground, does one pipe go into the well or two?

It is in the well about 75Ft down

There's a small tube that runs from the pump to the control box. Check it to be sure it's clear. Good luck, Tom

There are several possibilities:

1. Leaking well pipe which prevents the pump from getting above 40#.
2. Low water table, but this is not likely. You would generally notice the pump pumping some air.
3. Pump going bad.

Why did you change the switch? What problem were you having at that point?