Atherton is the top-earning zip code on the West Coast, and no wonder: The small residential community is just a stone's throw from Menlo Park, the home of Facebook and many big venture-capital firms.

Most residents are in the tech industry, and include Microsoft billionaire Paul Allen and Google chairman Eric Schmidt.

Ken DeLeon, a local broker, said that buying in Atherton is almost like buying a name brand. "When you're buying Atherton, you're buying the most expensive neighborhood in California," he said, noting that he recently sold a $14 million home in just three days.