Water: Tap water for frogs?

[Bolisnide]

The easiest and most economical way of getting the chlorine out is to buy a de-chlorinator at a pet store and follow the instructions on the bottle...
Spring water is fine, but if it doesn't say 100% spring water, it still could have chlorine in it. And, in my experience, 100% spring water can be expensive. There are plenty of minerals in tap water. De-chlorinated tap water is actually the preferred water by many in the herp hobby.

[DC101]

What about rain water? Is it any good?

[DonLisk]

Tap water is usually the most recommended water for your frogs but should always be provided after the use of a declorinator. Although airing water for 24 hours will remove chlorine, you still need to find out what your water treatment plant is using for a chlorine type chemical. There are chlorine alternatives that these treatment plants use that are not removed by airing what so ever, so the declorinator makes that type safe.

As for rain water, you could collect it and use it but I myself stick with tap.

[DC101]

I got 3 rain water tanks.