Since people are always asking about irrigation, I thought I would just make a post with a link to the CA ET0 Zone Map.

ET0 stands for reference evapotranspiration and it's the amount of water turf grass requires for optimal growth. A moderate amount of water is 40-60% ET0. A low amount of water is 25-40%. This way if you see that a plant needs a moderate amount of water and your ET0 for the month is 8 inches then that plant will need 4 inches of water for the month.

http://www.cimis.water.ca.gov/App_Themes/images/etozonemap.jpg