1000, wow -- here in Michigan you can pretty much stick a pipe in the ground and water comes out. The well here is from about 1960, shy of 200 feet deep, and so hard it rings when it hits the sink. :^) The aquifer is the Marshall Sandstone.
Any water I know of around here above the Roubidoux is so hard and nasty you have to chew it but you will never need a laxative. People around here that know would rather have rural water than electricity. Our well, before rural water, was 300’ deep and poor in volume and quality. It is the coal seams I guess. We had to replace the lifetime glass lined water tanks just about yearly. The water would corrode the bronze jets in the jet pump inside a year. I know, Dad and I pulled the two strings of slick poly pipe many times and it was heavy!
All this in spite of having nearly 50 inches of rain a year.
Some of the few older folks around here, I am nearing that status myself, say if you go below 150’ forget about it so I am considering building a drilling rig and try a hole or two. We water the garden from the pond and that seems to work OK.
I surveyed with Dad in Michigan in the 50s. Flat as a pool table. You could run a line of levels for miles and not vary more than a few tenths.