When we looked at houses in Colorado, I was freaked out by the water laws there. The idea (implicit to not being able to collect rainwater) that a person might not have rights to the rain that falls on their property struck me as being beyond absurd. Fortunately, here in AZ people are encouraged to catch and collect rainwater. So when we added some space to our house recently, we put in a 1200 gallon tank and hooked it up to all the gutters. An inch or two of rainfall will fill it up.
I'm glad that the laws in Colorado have changed - good for you and your garden.