What are the Halachic parameters of the Mikveh? Are jacuzzi, hot tub or a large basin for rain water sufficient? What are the actual measurements and how much rain water does one need? Can the Mivkeh be self contained or does it have to be connected to the ground?

Shalom U'verachah, The building of a Mikvah is a complicated business that requires a basin that cannot become Tamei and to be filled with 40 Se'ah of water, but not all of it needs to be rainwater. A jacuzzi etc. is not kosher for a Mikveh. I suggest that one eithers uses the local Mikveh or brings in an expert on this matter in order to build a kosher Mikveh. Kol Tuv