Safe water question

Can I assume that the water a mouse lives on is safe to use with my snakes? I've been using water from a hose, because I knew it was safe. I don't however know if my utility faucet is safe. I'm seeing if the water is safe by giving it to one of my feeders for a few days or so. Any help?

I'd just get a Brita pitcher. It's not that expensive, and you never have to ask if it's good enough. My general rule of thumb is that I don't give my Ball anything I wouldn't drink myself. I'd have the same rule about food, but I'm not about to eat live mice.