I have a shallow well with a 1 1/4"dia X 3' sand point, and a 3/4 Hp Jet Pump. The tip of the sand point is at 22 feet below the pump intake, with 6 feet of water in the pipe or 16 feet below the intake.
I have used this well continously for the past 27 years while replacing the sand point about every 6-7 years and the pump 3 times.
THe water level has dropped about 4 feet in this time span and I'm about at the limit for the jet pump. This pump is 7 years old and suddenly started to take a long time to build up shut off pressure of 50 lbs, and will not sustain constant usage in volume and pressure, ie sprinkling, and laundry. I replaced the sand point, pipe, check valve, and all fittings to the pump in order to rule out any vacuum leaks but this has not corrected the problem.
I have 2 questions:
(1) Do pumps wear out while operating fine (No leaks and or strange noises) and suddenly lose their pumping ability?
(2) I have very good water at this depth. Neighbors who have deep wells,(125 to 150 feet) have terrible tasting, smelly, high iron content water. Is it possible to use a submerged pump at this depth, and if so, how difficult is it to install. What would you recommend?

Thanks for any information you can provide