I have a deep well, 240 ft with 60 ft of drop pipe. The well is about 7 years old. I have just started having a problem with pressure. If I use more than one faucet my pressure will drop to nothing. If I turn my outside faucet wide open I will loose pressure. My pump impeller has been replaced but that did not help the problem. The pump does not lose prime but runs a long time before it builds pressure to cut off.

What materials are the pipes in your house made of? How old is your house? What's the pressure read on the gage when the pump's up to pressdure and shut off? Back to you. Tom

Sounds like you are not using a submersible pump, so the pump is on the surface?

"The pump does not lose prime but runs a long time before it builds pressure to cut off."
It sounds like your pump is not delivering much volume. You can determine that without much trouble. See below.

Big question as stated above is what pressure does your gauge read when the pump cuts off? I would also want to know how much water can be used before the pump cuts back on. Determine this by allowing the pump to pump up to cut off pressure, then begin running a faucet through a garden hose into a 5 gallon bucket. You should be able, generally speaking, to get five or six gallons (or more) before the pump cuts back on. YOu should get this volume within a minute or less.