Most (Many?) states have a so called Policy of last resort to insure High risk properties. These policies are called Fair Access to Insurance Requirements (FAIR) Plans. It is a joint program between the state and the insurance companies.
According to the California department of insurance (a state agency):
What If I Can't Find Insurance?
If after shopping the market you are still having difficulty obtaining
residential insurance, you may want to contact the California FAIR
Plan to explore your coverage options. As the insurer of last resort,
the California FAIR Plan should only be considered after a diligent
search for coverage in the traditional insurance market. If you are
turned down or non-renewed by your current insurance company, or are
otherwise in need of coverage, you may apply for coverage under the
FAIR Plan through an agent or broker licensed to sell property
insurance, or you may contact the FAIR Plan directly at 800-339-4099.
Please note that the FAIR Plan only provides coverage for the losses
caused by Fire or Lightning, Internal Explosion, and Smoke. For an
additional premium, Extended Coverage (windstorm, hail, explosion,
riot or civil commotion, aircraft, vehicles, and volcanic eruption)
and Vandalism or Malicious Mischief may be added to the policy. Since
the FAIR Plan policy does not cover all the perils insured under a
traditional homeowners' insurance policy such as theft or liability,
you may want to consider purchasing a separate Differences in
Conditions (DIC) policy in addition to the FAIR Plan policy. DIC
insurance is designed to fill in gaps in insurance coverage. It
provides expanded coverage for some perils that are not covered by the
FAIR plan policy. Above is a list of carriers currently offering DIC
policies. You may also wish to contact an agent or broker to help you
shop around for this type of coverage.
they also include a link to the California FAIR plan Association. where they explain in detail what is and is not covered.