What is the most expensive zip code in CA?

If you had to guess which California city has the most expensive real estate, what would you say? San Francisco, maybe? Certain parts of Los Angeles – remember the show 90210?
Watkins-Cartan House, 98 Alejandra Ave., Atherton, CA
Nope, the honor goes to the 94027 zip code – Atherton, CA. For those not familiar, Atherton is right above Palo Alto and the average cost of a home there is…wait for it…$6.17 million. According to Zillow, home values in Atherton reached a low point in summer 2009, dipping below $3 million.
I asked my friend Jay Vorhees of JVM Lending what kind of average income would be necessary to afford a home in Atherton at 25 percent and 50 percent down.
Given that the average income in Atherton is about $250,000, I was wondering how exactly a median home price of $6.17 million was affordable there! Here’s his assessment:
Assuming no consumer debt, a 4.0% rate and a 42% debt ratio, with 25% down, PITI would be about $29,000 per month (rounded). This would require $69,000 of monthly income or $828,000 annually.
With 50% down, PITI would be about $22,000 per month (rounded). This would require about $52,500 of monthly income or $630,000 annually.
So how does the average income earner in that area afford Atherton? Most likely people have had these homes for years, thus the lower income. For new purchases, stock options from IPOs are not usually included in your annual income, thus allowing the the nouveau riche of Silicon Valley to buy with cash or put 50% or more down.