From The Pueblo Chieftain (Chris Woodka):
Don’t run out and buy a rain barrel. Even if you’re lucky enough to catch a downpour, it is illegal to collect rainwater from rooftops in Colorado in most cases.
The Pueblo Chieftain ran an article in its Real Estate section Friday that suggested rain barrels could be used to meet water needs. That may be true in other parts of the United States, but collecting water in rain barrels in Colorado is allowed only under certain circumstances.
Two bills passed by the Legislature and signed by the governor in 2009 allow for rainwater collection:
SB80 allows residential well owners to collect water from the roof of primary homes only, if no other water supply is available from a city or water district. The collection has to be part of the well permit for the property.
HB1129 provided for developers to build in rainwater collection if the development is approved as one of 10 statewide pilot projects.
Otherwise, rainwater collection is illegal.
The Colorado Division of Water Resources considers rainwater to be part of the property of the people of the state as defined by the Colorado Constitution.
“As a result, in much of the state, it is illegal to divert rainwater falling on your property expressly for a certain use unless you have a very old water right or during occasional periods when there is a surplus of water in the river system,” the division states on its website.
“This is especially true in the urban, suburban and rural areas along the Front Range.
“This system of water allocation plays an important role in protecting the owners of senior water rights that are entitled to appropriate the full amount of their decreed water right, particularly when there is not enough to satisfy them and parties whose water right is junior to them.”
More water law coverage here.