Landscape irrigation baseline in California

Good questions and I can only answer it based on what the USGBC is saying in regards to comparability of the LEED standard internationally. Basically the goal is to compare one building in China vs one in New York City. With that being said I think you will use the common practice in the US as your baseline even if you are suppose to be 50% below baseline in California. Also because if I would start with another baseline in a project for instance in Europe, where stormwater retention and infiltration is required, turf usually does not get irrigated and insulation values of standard window are so high, that they are considered highly efficiency here in the US, you will end up having non-comparable point ratings for buildings based on the country, state or city, which they are located.