Suggestion....go back to the old rain barrel for roof runoff.
If its Governor Jerry Brown...FLUSH it DOWN!!
Be careful with rain runoff. The EPA has a say on it:
http://www.huffingtonpost.com/2012/08/16/gary-harrington-oregon-water-rainwater_n_1784378.html
Yeah . . and once a week is often enough for a shower. The rest of the week, take sponge baths in the lavatory & washeth what stinketh. Grain vinegar makes a good deodorant.