rain water

i just read on a website that rain water is good for indoor marijuana plants.

is this true? whatever the answer, why? i live in an apartment complex and may look kinda funny going outside and collecting rain water so i wanted some input before i do such thing, haha.

it just seems to me that rain water would do more harm than good, considering the state of our pollution, etc...

The quality of the rain water varies from place to place but it is usually solid ph wise. Just leave your tap water sitting out over night and don't warry about a rain water collection/