In one of the driest states in the U.S., it's apparently illegal to harvest rainwater (at least on a large scale) as it diverts water from someone else downstream. (Is there a private water-bottling company downstream?) Thankfully, they're not going after your garden-loving grandmother, but it does set a precedent for those who might collect it for commercial use.
::Infowars via Youtube
Related Links on Water
EPA Report Looks at Managing Water Supplies in a Warming World
Report on Business Reports on Water
Making it illegal to collect rainwater (Takoma Gardening Blog)