The Colorado legislature has two bills before it concerning rainwater collection. Senate Bill 80 will allow people in rural areas not hooked up to a municipal water supply to apply for a rainwater-capture permit. House Bill 1129 would establish up to 10 pilot projects in new residential developments to collect rainwater, in order to determine whether rainwater collection systems are a sustainable water source without infringing on downstream water rights of farmers and ranchers.
In Utah, Senate Bill 128 would allow individuals to collect and store up to 2,500 gallons of rainwater at one time. The tank limit is meant to alleviate the concerns of the agricultural industry regarding impact to groundwater sources.
According to IAPMO, current laws in Colorado and Utah make it illegal to collect rain that falls on your roof or in your yard unless you own the water rights for it.
Source: IAPMO