I use filtered drinking water, get my 5 gallon jugs refilled at save mart for .29$ per gallon. A 5 gallon container lasts for a couple weeks even with a large collection of smaller snakes. The biggest benefit for me is that filtered water does not leave any deposits. My cheap clear plastic bowls clean perfect every time with just my 2 fingers under a faucet.
And, if you fill your mister bottle with it, it will not leave any waterstains on your glass. Well worth the cost in my opinion.

(Hopefully)not having to worry about the health aspect is just a bonus for me.