Before making the drive from Santa Barbara, Calif., to San Francisco after the final day of the Water Rights & Trading Summit – California (hosted by American Water Intelligence and West Water Research, who produced an insightful and engaging event), I stopped to refuel. The price of a gallon of gas in California is among the highest in the United States, and the high price is credited with helping spur the development of fuel-efficient technologies.

As I pulled out of the service station and onto the highway, a downpour started, which lasted off and on most the way home. The rainwater, of course, is free. Anyone can collect it and use it for just about anything they want, regardless of whether it’s put to good use or not. The cost of water generally is just about free, too. The average water bill for a single-family home can be anywhere from $30 to $100 a month, depending on the market and th