I have a 1hp shallow well system the pump will stop pumping but hold its prime after about 20 gal of water has been pumped. I have to turn the pump off for about 30 min to an hour how can I determine what the problem is?

Sounds like the water table is dropping below the level of the footvalve, then it takes a while for it to recover. The footvalve will prevent your pump from losing prime, even when its dry.

How many pipes come out of your pump and go into the well, one or two?

There are two lines coming in.

I agree with jlsenbe,
This is the clkincher,
I have to turn the pump off for about 30 min to an hour
This gives the water table time to build up.. regards, Tom

Big Rick, it might be possible to go a little deeper with your wellpipe, and perhaps get to the point where water is more abundant. It would probably take a pro to determine that.

Thanks I was hoping it was the pump going bad, since I have iron water with a lot of sediment in it.

Let us know how it turns out. You'd be amazed at the number of posts that get this far and then we never hear any more. Strangely, it is very difficult to gauge the depth of water in a well. You can't see it, and there are no inexpensive methods I know of to try and measure it.

Will do . I am going to try and pull the foot valve then drop a weight down the well to see if I can determine water level and depth.

I had 69' of standing water in a 100' well. So I put a new foot valve on after pulling the old one out. After dropping the valve back in the well it worked for about 40 gallon of water and quit again, this time I lost the prime also. So we borrowed a 250 gallon tank and dumped 200 gallon of water in the well. And as of today I haven't had anymore trouble. Thanks again for the help guys

Thanks for the update. Keep us informed of further developments.
Good luck, Tom