Wyoming Rainwater Harvesting Under State Water Rights System

Because the Wyoming Constitution declares all waters of natural streams, springs, lakes, and other collections of still water property of the state, captured precipitation falls under Title 41 once it would otherwise reach a watercourse. Wyoming has not enacted a specific statute prohibiting residential rooftop harvesting, and the State Engineer generally treats small domestic rooftop catchment for nonpotable uses as outside permit requirements. Larger systems, ground catchment, or diversions affecting downstream appropriators implicate state water rights and may require permitting. Local ordinances cannot authorize harvesting that would impair adjudicated water rights administered statewide.

Harvesting at a scale that injures senior water rights, or constructing unpermitted reservoirs and diversions, may trigger State Engineer enforcement, abatement orders, and civil liability to injured appropriators.