[ckissick]

I'm a licensed hydrogeologist, so I know a bit about this stuff. Do you have data on the well? How deep is it? What's the depth to water? At what depth(s) is it screened?

There's groundwater under valleys and hills. It's just deeper to water if you're on a hill.

Another interesting fact: In San Francisco, they have some old municipal water wells right on the beach. Fresh water is less dense than salt water, so it "floats" on top of the salt water from the ocean. The higher elevations on land push the fresh water out to sea. There's a wedge of fresh water over the salt water. Of course, if you drill deep enough you will get into the salt water. And if you pump too much, you will raise the interface between the two.