painted metal roof for rainwater harvesting

tim kamrath
I have been told that galvalum is OK for rain water collection. They say that nothing leaches from the metal into the water. I am wondering if there is any painted roofing material that can make this claim. I am going to harvest rain water for potable usage. I would REALLY like to use a painted metal roof so that I can get the best emissivity from my roof. But I don't know, and can't find anyone who can tell me, if their painted metal roofing material will leach any chemicals from the paint into the water as the material ages. Do you know of any? Or am I just going to have to use galvalum? thanks.
Todd Miller
Isaiah Industries, Inc.
I know that some individual manufacturers and metal suppliers have studies done in this area. I would suggest checking direct with companies like Englert. ATAS, and Drexel. I believe that you will find results with PVDF-painted metal similar or superior to bare galvalume.
David Stermer
Thanks for the question. According to NSF (, filtration is a typical part of rainwater harvesting systems that produce potable water. Impurities can enter the water from the environment (acid rain), from the catchment area (leaching out) or from debris. Our typical recommnedation is that the water be tested periodically to ensure the filtration is effective at producing potable water. Regards, David Stermer

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