If you have room, about 5' above the screen. If the pump is too close or down in the screen on some wells, it may cause the well to make excess sediment/sand. This is only on shalow wells Most of our well around here are 200' to 400' and make lots of water, so there is no need to set the pumps that deep. If you have a well that does not produce that much water, the pump may need to be set deeper. It really all depends on the well being used.
The site appeared to be down for awhile. I could not access the website for about a day and a half.
Travis