It's a bit more of an issue of where you live I think?
Some areas can have some pretty bad water quality. Or an individual building can with old pipes and such.
If your tap water has a funny color, odor or taste? Don't give it to your animals.
Purified and bottled water would be best.
RO water is a bit acidic but mostly okay
Spring water is okay but I don't know the odds of contaminates there...
Normal tap is...eh. I like to run mine through a filter regardless. Remember that we add things like chlorine and flouride to tap water. You can use a dechlorinator as well but make sure to use as directed