What about doing it secretly?
I spent a while (in Minnesota) trying to find out the legal issues about drinking rain water. There were so many regulations for rainwater systems, all about making sure the rain water was completely separate from the drinking water. Finally I started making phone calls, and learned there was not a single agency interested in regulating my personal life. They were all about commercial things. Though I could never sell the house without a proper well and septic, they're here already.
Back to actual health and safety:
The matter of galvanized roofing was interesting because I recently read that galvanized causes cancer or something, and I'm thinking of getting it away from my plants. (No, they don't get cancer. I didn't memorize the article, just made a decision.) But my roof has a green coating on it so maybe it's not the galvanized thing.
And I came here because most of my drinking water comes from my solar panels, I clean the barrels occasionally, and plan a better system when I go full-scale rainwater. But now I'm diagnosed with kidney disease, no visible cause, and I'm trying to find out whether my good-tasting rain water has either lead or hexavalent chromium in it from the solar panels.