I just bought a home that has been sitting for 4 years. The well turns on and builds pressure, but when it shuts off it loses pressure and turns on immeddiatly. I have the water shut off to the building so its just the tank and well.its a submersible pump with plenty of water. Question: Why would it not hold Pressure if the is no apparent leaks?

Having sat for 4 years, you may have had rust or dirt accumulate in the pump check valve. This valve, when working properly, prevents water from draining back into the well. Unfortunately, they are usually on top of the pump, but look for one at the wellhead or at the tank. You may also have a leak in the pipe. There may be a small plug-1/2 or 3/4- in the cap on the wellhead. Unscrew the plug, turn the pump on and when it cycles off, check to see if you hear water splashing. If you do, you have a pipe leak. If not, it could be the checkvalve or a leak below the water level.

Good answer. What kind of pipe goes into the well, pvc or galvanized?