The South Napa Earthquake shook Northern Californians awake on the Sunday morning of Aug. 24, and it also served as a reminder of the kind of damage temblors can cause. In its wake, people around the state are assessing whether to invest in earthquake insurance.

Over the past two decades, the percentage of California homeowners holding an earthquake insurance policy has dropped from around one-third of homeowners to about 9 percent now. Part of the reason for the dip could be complacency — prior to Sunday’s quake, Californians hadn’t experienced a major earthquake in more than two decades. But there are other reasons for the decline. Earthquake insurance is expensive, and many believe that it isn’t worth the cost.

On Friday, a panel of experts discussed earthquake insurance on KQED’sForum. Read on to learn how earthquake insurance works.

How much does earthquake insurance cost?

The statewide average is about $800 per year, but in San Francisco it costs more — about $2,000-$5,000 per year for a 1,400-square-foot home. The exact cost tends to vary based on a variety of factors, including age, size and location of a home. (If a home is located next to the San Andreas Fault, it’ll cost more to insure than a house that is nowhere near a fault.) Use the California Earthquake Authority’s online premium calculator to get an estimate of what earthquake insurance would cost for you and your family.

Various earthquake coverage options are also available — there isn’t a single one-size-fits-all plan. Beginning in 2012, the CEA began offering the homeowners choice policy, which gives insurance holders more flexibility and creates separate deductibles for the structure of the home and personal property.

“You can insure your structure, and you set a deductible – 10 or 15 percent of that coverage amount has to be down before we can pay a claim. And then you can insure all the contents and things that are valuable to you inside that home, and set your own deductible,” said Glenn Pomeroy, CEO of the California Earthquake Authority.

How can I assess the earthquake risk of my home?

There is a host of factors to consider when determining your risk profile, including your home’s proximity to a fault line, whether it’s located on bedrock or fill, and the structure’s construction materials and quality. To identify specific hazards, like soil liquefaction and fault rupture hazards, view the earthquake hazard map on the California Emergency Management Agency’s earthquake preparedness website.

Doesn’t homeowners insurance cover earthquakes?

No, earthquake damage is usually excluded from homeowners insurance policies. Earthquake insurance must be added on separately.

What about renters insurance?

A standard renters insurance policy typically costs about $120 per year, but that basic policy won’t protect against earthquakes. Renters must add earthquake insurance to insure their possessions and to provide them a place to stay in the event that their home is damaged or destroyed. Although renters can insure their own possessions, it’s up to the landlord to insure the structure.

How does earthquake insurance work for condo owners?

A condominium association can insure an entire condo complex, and each individual condo owner can insure the contents of their homes, according to Pomeroy. Additionally, condo owners can insure against receiving an assessment from the condo association if there is a loss that’s spread across all condo owners in a building or complex.

Why doesn’t everyone have earthquake insurance?

Unlike homeowners insurance, earthquake insurance is not mandatory, and that isn’t likely to change in the coming years. Banks require homeowners in flood zones to buy flood insurance, but they don’t require homeowners in quake zones to obtain earthquake insurance.

Many Californians have long viewed earthquake insurance as a losing proposition. The most common type of coverage is a high-deductible plan, which is similar to catastrophic medical insurance. And many people don’t know about newer policy options that enable insurance holders to separately insure their homes and their possessions.

“If you buy an earthquake policy in California and you have a 15 percent deductible, as most people have, it’s very unlikely you’re going to see a payout, except for the Big One,” said Amy Bach, executive director and co-founder of United Policyholders. So there’s little incentive for many people to invest in the insurance.

Will the government help out if you’re uninsured? 

Probably not. “There are a variety of misperceptions about the government coming to your rescue afterwards. That is absolutely incorrect,” said Bob Hartwig, president of the Insurance Information Institute. “There’s nothing the buys peace of mind like an insurance policy that is going to pay and is going to pay quickly.

“Through the government, the most you can possibly get is maybe about $32,000. You might get a loan, which has to be paid back. All told, the amount is not going to be sufficient for you to recover. You’ll have to pay it back. And you won’t know when you’ll get it, if you get it at all.”

Part of the government’s reticence can be attributed to politics: The federal government has been shrinking in recent years, making a new type of disaster insurance unpopular among lawmakers. (The flood program is $24 billion in debt.) So, the situation is unlikely to change soon.

Aside from earthquake insurance, how can I protect my home?

There are easy mitigation measures that every homeowner can take, like strapping your hot water heater to the wall so it doesn’t fall over and start a fire. Installing a gas shutoff valve is also a good way to protect against fire. Many owners of wood-frame buildings install shear panels to strengthen the structure and protect it against earthquakes. The website Earthquake Brace+Bolt provides resources for seismically retrofitting homes.