In the PNW I'd go for rainwater collection, even during the summer you are seldom without. Compared to drinking polluted river water, I'll take my chances drinking potential pollutants flowing off a roof and originating in Far Eastern pollution sources coming over on the jet stream. You can also minimize contamination from a local roof source by putting down the proverbial large blue tarp - and if my neighbor's are gone, to heck with the issues around what will the neighbor's think. They've never lived in Australia, that's for sure. Rain is good...