osewme: I use well water too so no problems with it. Don't know about regular tap water though, seems from what I have read it would be fine unless you have some problem with your tap water.
To answer all your questions, I suggest you go to King Arthur Flour website and read all about sour dough. They can get you started and answer your questions. Here is a link:
https://www.kingarthurflour.com/learn/guides/sourdough