The Four Corners states each have differing rules about who takes ownership of rain once it hits the ground. Some say it's off-limits to the land owner, while others encourage or even require rain catchment on buildings.
"Who owns the sky, anyway? In most of the country, that is a question for philosophy class or bad poetry. In the West, lawyers parse it with straight faces and serious intent. The result, especially stark here in the Four Corners area of Arizona, Colorado, New Mexico and Utah, is a crazy quilt of rules and regulations - and an entire subculture of people like Mr. Bartels who have been using the rain nature provided but laws forbade.
The two Colorado laws allow perhaps a quarter-million residents with private wells to begin rainwater harvesting, as well as the setting up of a pilot program for larger scale rain-catching."