From The Colorado Springs Gazette (Jim Flynn):
At the heart of this [water law] system, and protected by a section of the Colorado Constitution, is a concept called “prior appropriation.” The way this works is that some water users have priority over other water users, with the effect that, in times of scarcity, holders of senior water rights receive their water and holders of junior water rights do not. The seniority of water rights is generally based on a first-to-use-wins concept, meaning the most senior (and therefore the most valuable) water rights go back to the 1800s.
Any upstream activity even remotely threatening to downstream water rights holders is cause for great alarm. This came to light in the 2016 session of the Colorado Legislature when a bill (House Bill 16-1005) was introduced intended to regulate the collection of rainwater in barrels.
What finally emerged, after heated debate, is a new law allowing rainwater running off the rooftop of a residential property containing no more than four dwelling units to be collected in no more than two barrels having a combined storage capacity of no more than 110 gallons. These barrels must have a sealable lid; the water from the barrels can only be used at the property where the water is collected; and it can only be used for outdoor purposes “including irrigation of lawns and gardens.” The water “shall not be used for drinking water or indoor household purposes.” (Whether the water could be used for bathing activities if conducted outdoors is not clear.)
The state engineer, “to the extent practicable within existing resources,” is instructed to provide information on his agency’s website about the permitted and prohibited uses of rain barrels and water collected therein. The state engineer is also given authority to curtail rain barrel usage in situations where it might impair the rights of downstream water users. And the state engineer is required to diligently study whether rain barrel usage is causing injury to holders of downstream water rights and to report back to the Legislature on this issue by no later than March 1, 2019.
The Colorado Department of Public Health and Environment also gets into the act. That agency is instructed, “to the extent practicable within existing resources,” to develop “best practices” intended to address nonpotable usage of collected rainwater and issues relating to disease and pest control. When and if such best practices are developed, they are to be posted on the department’s website and on the state engineer’s website. Alternatively, the state engineer’s website can provide a link back to the department’s website.
Finally, knowing the penchant of homeowners living in common-interest ownership communities to fight over almost everything, the Legislature added language to the new law addressing rain barrel usage in these communities. An owners association in a common-interest ownership community cannot prohibit rooftop water collection using rain barrels. The association can, however, “impose reasonable aesthetic requirements that govern the placement or external appearance of a rain barrel.” So, for any of you who have the misfortune of serving on your neighborhood architectural control committee, it’s time to develop design guidelines for rain barrels.