Building garage over well water supply line

I have a question regarding building a detached garage over an existing well water supply line. Our town's zoning regulations regarding setbacks, etc. are such that about the only place we can practically place a new detached garage is on top of the area where the well water supply pipe is currently running between the well and the house. Is it even permissible to do this in NY State, and if so, how we can find out exactly where and how deep the water supply line is? Also, any suggestions regarding type of foundation - slab, or block perimeter?

As long as the pump power wire is buried alongside the supply line, you can have a locate done on the wire and find its depth.