Is bottled water safer for cats than tap?

Not really. For most homes with safe municipal tap water, bottled water offers no hydration or health advantage for cats. It’s the same water in a bottle, sometimes with a slightly different mineral profile. There are two situations where it might be worth it: if your tap water is on a private well and you haven’t had it tested, or if you’re traveling somewhere with poor water quality and would buy bottled for yourself. Avoid distilled water as a regular drink. It’s stripped of minerals and isn’t ideal as a daily water source. Plain tap or filtered tap is the right default.

When to call a vet: if she’s refusing water she’s always drunk, the change matters more than the water; bring it up at her next vet visit.