Who owns the water that falls on your rooftop? In most of the western United States, it’s not you, and if you try to catch and store that water, you may be interfering with someone else’s water rights. NPR aired a story on the issue this morning, “Water Wars Out West: Keep What You Catch,” about a Colorado law that breaks with the usual legal regime. The law allows water collection by residential property owners who need to dig a well or get their supply trucked in (in other words, if you’re served by what city dwellers think of as a regular water system, it’s still illegal for you to catch and save rainwater and snowmelt in Colorado.)
Southwest Colorado Water Information Program: Understanding Water Rights
U.S. Bureau of Land Management: Western States Water Laws
And also, for generally interesting reading on water rights questions, Aguanomics, a blog from two UC-Berkeley economists.