I'm thinking about adding a rain collector to use in my garden but I have some concerns about construction materials.
One concern is that I'm not a huge fan of using a plastic container to store water. The idea of water sitting in a plastic barrel that could be exposed to heat from direct sunlight doesn't fill me with excitement. I was wondering what other materials or containers I could use that might be better for storing rain water. One idea I had was to modify a metal keg to collect water. They would be smaller but I could use multiple if I wanted.
The other concern I have is about roofing materials. Is it safe to use water collected from a roof with shingles in a garden for vegetables? I'm wondering if there might be any run off from the materials used for roofing.
..... Okay I'll bite
Why on earth would they prohibit that?
OP's wildly misunderstanding. The idea behind such laws is that some asshole doesn't divert acres and acres of rainwater for his personal use. I think one guy, ever, has been prosecuted, and that's exactly what he was doing.
tl;dr: No one's coming for you after a rain barrel.
I'd say it's more just an overabundance of caution — rainwater collection laws aren't without precedent. Admittedly, given the context of OP's post, my comment doesn't warrant much concern.
That's because you wouldnt be prosecuted unless it was a massive operation... you'd be fined by your local bylaw enforcement officer until you remove said rain barrel... thats not even counting the sorry saps who have to deal with HOAs. Happens ALL THE TIME. Maybe you are just lucky where you live.
Large collections of rainwater could disrupt water ecosystems. Admittedly, my comment doesn't warrant much concern given the context OP's post. Here is an article talking about Colorado's water collection laws. Here's a Reddit thread that offers some more information.