My house is 10 yrs old with a well that is 450ft deep. Last week we started experiencing very low water pressure. I called our plumber and he thought that it was probably because our water level has dropped significantly due to a very dry summer. He checked for leaks and concluded that the well pump (1hp 10GPM) needed to be changed to a 1HP 5GPM because the flow rate was to low. He changed out the pump and it helped for about 2 days. Last night while taking a shower the water slowed to a trickle then stopped. I thought the breaker tripped but it hadn't. I shut the breaker off for about 5 minutes and turned it back on and it seemed to restore the water pressure, for about a minute. I called the plumber and he said to leave the breaker off as much as we can, that he is going to have to drop the pump further down the well. I'm just trying to find out if this is normal, and does my plumber know what he is doing or do I need to find a well specialist.

You need a well man.