Whats wrong with tap water? as long as your ppms are under 450 your fine. You can also find out whats in your water by searching online. The ppms are mostly dissolved calcium and magnesium.
With that being said i have a RO set up
but nothing wrong with tap just leave it out for bout 24 hours so the chlorine evaporates. And you don't really even have to do that as the content of chlorine in your tap is not enough to do any damage to the plant it self. Might even work as a very mild bactericide