Hi Kathy,
I would recommend using the water that you drink, if it's good for you.... chances are it will be good for them :)

Sheila

Ditto what Sheila said. Do you have some concerns in particular? Lori

Rainwater will be fine unless you have a really nasty metal on the roof (like arsenic).

For very young to adolescent birds, I think I would be a little leery of water off the roof - who knows if the birds perching on it and pooping on it may have some disease. Once the chicks are older, I would think that the roof run-off would be fine, but for youngsters still growing up, I wouldn't use it. House or well water water should be fine.