The story that keeps circulating on the internet is that a guy in Colorado was fined for doing just for that. But looking at it more closely you find he was damming creeks on his property and building holding ponds (essentially lakes), which is subject to standard environmental regulations.
I'm not sure what your link is supposed to prove. It unequivocally states that Colorado makes it unlawful to collect rainwater. Indeed this linked website of the state of Colorado confirms that "you cannot collect rainwater in any other manner, such as storage in a cistern or tank, for later use."
http://www.enlight-inc.com/blog/?p=1036
The story that keeps circulating on the internet is that a guy in Colorado was fined for doing just for that. But looking at it more closely you find he was damming creeks on his property and building holding ponds (essentially lakes), which is subject to standard environmental regulations.