That comment caught my attention since I'm a member of several watershed regulatory boards. If you know that much about capturing rainwater, you probably already know that rainwater harvesting is not only legal in most of the lower 48, but is encouraged in many.... probably in most.
Colorado does have an old rainwater law interpretation on the books from the 1800s. It's vague, and dates back to the Wild West and Gold Rush days.
Yes, the law is still valid but is no longer enforced - I don't know if that one ever was. Today it seems to exist mostly as a history lesson - and is likely to remain there because it makes such a good story to be passed down at water board meetings.
I'm sure that there are other states that have similar out-dated regulations still on the books. Our local town has some real interesting old ordinances about keeping livestock in town. For example there is one that puts a limit on how many hogs a homeowner can keep on on residential property in town.
In looking at those old laws and ordinances I am always struck by how activites back then tended to be limited rather than forbidden. That old law about hogs doesn't say that you can't raise hogs in your front yard, it just limits how many you can have at once. I believe it also says something about slaughtering on Sundays, too. And yes, that one is still valid as well.
Back to rainwater, that old Colorado law works the same way. It basically limits the amount of rainwater that you can keep stored in barrels at any one time. Today it's hard to understand why that mattered.... my guess is like a lot of things in Colordo it had to do with placer mining & gold panning.
rScotty
