A related question: Any thoughts on using non-tap water for washing? I'm thinking specifically of rain water collected in a barrel or the water collected from a dehumidifier? I know PE has advised against the latter for use in developers because of the presence of microorganisms and other contaminants, so I'm guessing the same water would be a poor choice for washing, but I'm not sure of that. Would using such water be OK if it were followed by a shortened wash using tap water? That would at least help reduce tap water consumption.