In the United States, Colorado is the only state where collecting rainwater is significantly restricted to the point of being illegal beyond a small, specified allowance. While the state is often cited as having a complete ban, the reality is that specific regulations permit a limited amount of collection for residential use.
Understanding Rainwater Collection Laws in Colorado
Colorado's unique water laws are rooted in the "prior appropriation" doctrine, which grants water rights based on historical use, often to those who first diverted water from a stream or river. This system views all water, including rainwater, as belonging to those with existing water rights.
Despite this framework, a specific allowance has been made for residential rainwater harvesting:
- Permitted Collection: Homeowners in Colorado are legally allowed to collect rainwater using two rain barrels.
- Capacity Limit: The combined capacity of these two rain barrels cannot exceed 110 gallons.
- Illegal Collection: Any collection of rainwater that exceeds this limit of two barrels or 110 gallons is considered a violation of the law. This means that while some collection is permitted, larger-scale rainwater harvesting systems for general use are illegal.
Rainwater Harvesting in Other States
For the vast majority of the United States, collecting rainwater is not illegal and is often encouraged through various incentives and programs. Many states and municipalities promote rainwater harvesting as a sustainable practice for landscaping, gardening, and even non-potable indoor uses, helping to conserve municipal water supplies and reduce stormwater runoff.
While specific regulations and permits might apply in certain areas, particularly for larger systems or for use inside homes, the concept of simply collecting rainwater in barrels for outdoor use is widely accepted and legal across almost all other states.
