Your homeowners policy will not cover damage to your home and belongings in the event of an earthquake. To be insured for earthquake losses, you’ll have to separately purchase an earthquake coverage endorsement—and in the Bay Area, this is expensive.

California law requires insurance companies to offer earthquake coverage whenever a consumer purchases a homeowners policy. Some companies offer coverage themselves; others offer it through the California Earthquake Authority (CEA), a privately financed, publicly managed agency that sells earthquake insurance through participating insurance companies.

Coverage can come with severe limits. Homeowners usually buy policies with deductibles of 10 or 15 percent (with a 15 percent deductible, you’d pay $90,000 on the loss of a $600,000 home); can collect only up to $100,000 for personal property losses; and can collect only up to $25,000 for increased living expenses while a damaged home is being repaired. Renters and condo owners can face similar low limits for personal property and increased living expenses.

Insurance companies and the CEA now offer more coverage options and higher limits than they did a decade or so ago: You can now buy a policy with a deductible lower than 10 or 15 percent, and you can add higher limits for personal property. But making these types of improvements to most earthquake policies makes premiums unaffordable for most.

Use the California Department of Insurance's excellent rate comparison tool to collect pricing for earthquake coverage for your home. The CEA also has a price-quoting tool for earthquake coverage offered by companies that participate with it.

If you own a masonry home, earthquake coverage costs will be much higher—as much as three times higher than for a frame home. In our experience, CEA coverage costs less than policies purchased through most insurers for masonry homes, but for frame homes the other companies often beat CEA premiums.

Because earthquake coverage is so expensive, consider cost carefully when choosing a homeowners insurance company. The company with the best rates on a basic homeowners policy may not be best when you add the price for earthquake coverage.