OK, can he continue to drill your well to 400 feet? If so, that's $10K if I understand correctly. Or what am I missing?
There is some inexpensive mountain (really just a very big hill) land in TN near a small airport. I was considering purchase. By luck, I found out the area had been extensively mined during and after the civil war. Due to the mining, the local aquifer is either gone or massively contaminated, and no amount of drilling gets safe water. Not doing that.
In any case, I wish you the very best in your quest for water!