California is a state criss-crossed by massive faults and smaller, lesser known faults. Yet, in spite of the risks, nearly 88 percent of the states' homeowners opt not to have earthquake insurance, potentially leaving millions of Californians financially unprotected in the event of a catastrophic earthquake. California homeowner insurers are required to offer earthquake insurance. Most earthquake policies are sold by the California Earthquake Authority through its member companies.

The map below shows the percentage of earthquake insurance policies for each county.