NSF Protocol P151 and Standard 61 certification provides assurance to both public health officials and consumers that the system components are safe for use in rainwater collection systems and for potable water applications respectively. If potable water is needed, take care in selecting materials and elastomeric roof coatings which will come into contact with the water as it is collected, since some impurities can be picked up by the rainwater as it travels through the collection system.
Rooftop rainwater collection systems are designed to capture rainwater and transported through gutters and other pipes into cisterns or tanks, where it is stored until needed. The water collected can be used for irrigation, laundry, hygiene, or even potable water, depending upon the materials used and the treatment undertaken by the building owner.