One of my employees came up from CA a few years ago. In a Manager's meeting today we were discussing irrigation, proper zoning methods, different kinds of backflow devices, etc. He said that where he came from (San Diego area) that they never had to install backflow devices for residential irrigation systems. It was only required for commercial jobs. Is that true? I thought pretty much every major city or county in the U.S. had backflow requirements for residential irrigation systems. ESPECIALLY California, I would think. They are the world leaders in regulation of any kind... Anyone know if this is true?