Now that gives me an idea. I could bottle up spring water and make a fortune. Seriously it is a fascinating spot on this earth. Here is a short news clip telling a little about it and shows a busy highway, U.S 19 and what is 250' below the surface.If it's directly below your house, then I would say you own it. We can't own the airspace above our property, but the ground you bought goes down to the core.
A very large and dangerous cave system only recently explored and just a small portion at that.