Why Don't California Homes Have Basements?

None of the homes that I've seen in California have basements.  I've always wondered about this because coastal Southern California has some of the highest housing prices in the nation.  This is due to the scarcity of land to build on -- the result of being sandwiched between an ocean and a desert.

Houses here are sardined next to each other, like the little houses you put on your property in Monopoly. Ten feet is the average distance separating properties, but zero property lines -- where your neighbor's wall marks the boundary to your property -- are becoming more and more common.  To maximize profit, builders are squishing even more units into a smaller area.

With such high price per square foot and so little room to expand, it would make sense for California homes to expand their living space downward.  An engineer friend of mine says that it's because of zoning laws: a basement would count as an additional story.  A two story house with a basement would need to be zoned as a three story structure.  Still, it nagged at the back of my mind. I finally Googled the question to confirm this theory.  Some of the most popular answers are:

A basement in earthquake country would have to be certified as earthquake proof, waterproof, gremlin proof, and a whole bunch of other proofs.  As California is not the most business friendly state, most builders don't want to deal with the liability that goes with building a basement.

Because of the above mentioned factors, building a basement would also cost a ridiculously high amount, say about $2000 per sq/ft. as oppose to $200 sq/ft. to build.  Most home buyers refuse to spend the 4 million dollars when a similar house in the next development is going for only four hundred thousand.

The most logical answer that I've read is that basements are not needed in this sub-tropical climate.  In the frost belt, houses need to be built on a foundation that extends below the frost line, aka a basement.  Otherwise, the constant expansion and contraction of the ground from freezing/thawing would heave the house off its foundation.

Basements also shield water pipes from freezing and in a bygone era, it was where the huge furnaces sat and where coal was stored for the winter.

But the best answer on why California homes don't have a basement that I've seen so far has got to be. . .

"so we won't have to get any closer to hell any sooner than we have to?"