(TNND) — A "major" new report is offering the most robust insights yet on the growing problems of cost and accessibility for homeowner's insurance.

The report was released Thursday by the U.S. Department of the Treasury’s Federal Insurance Office, which said it contains the most comprehensive data on homeowner’s insurance in history through a first-of-its-kind collaboration with the National Association of Insurance Commissioners and state insurance regulators.

The Treasury said homeowner’s insurance is becoming more costly and harder to get for millions of Americans, with costs mounting from climate-related events.

In just the last 10 days, wildfires have ravaged the Los Angeles area, leaving about 12,000 structures destroyed.

Major hurricanes slammed residents in Florida this fall, carving paths of destruction and flooding throughout the Southeast.

The Treasury’s report looks at data from 2018 through 2022, a five-year period in which the annual number of major disaster declarations for climate-related events was almost double the annual average over the 50-year period from 1960 to 2010.

The National Oceanic and Atmospheric Administration says last year saw 27 weather and climate disaster events in the U.S. that each topped $1 billion in damages.

NOAA said total costs for those 27 events last year is estimated at $182.7 billion, a figure it said might increase still by several billion dollars.

Among the Treasury report’s key findings is that homeowner’s insurance costs are rising fast across the nation, but folks in higher-risk areas are feeling the financial pain more.

And policy nonrenewal rates are higher in areas with the highest expected losses from climate-related perils.

“This is a really big deal,” Marc Ragin, an expert in risk management and insurance at the University of Georgia, said of the Treasury’s new report.

“They've never collected data at this level before, because this is policy-level data,” he said. “And that's just generally not something that insurance companies provide, because it includes trade secrets and competition.”

The Treasury also released a large subset of the aggregated ZIP code-level data it used in its report.

“I think it helps regulators understand where those pinch points are and where those struggles are,” Ragin said. “I'm not sure that it's going to have a direct effect on Americans and residents in the U.S. I think it's more highlighting the extent of the problem and highlighting, I think in large part, how long we've got to go before we figure out a solution.”

Average homeowner’s insurance premiums per policy increased 8.7% faster than the rate of inflation from 2018 to 2022, according to the report.

But some customers faced substantially larger premium increases than the national average.

Homeowners in communities affected by substantial weather events are paying far more than those elsewhere, according to the report.

From 2018 to 2022, folks living in the 20% of ZIP codes with the highest expected annual losses to buildings from climate-related dangers paid $2,321 in premiums on average, 82% more than those in the 20% lowest climate-risk ZIP codes.

And average nonrenewal rates were about 80% higher for people living in the highest-risk ZIP codes than for those living in the lowest-risk ZIP codes.

Bloomberg reported that seven of the 12 biggest home insurers have limited their coverage in California over the past couple of years, partly because of wildfire risks.

Ragin said if you have a mortgage, you're required to have homeowner’s insurance.

“There are people out there who don't have a mortgage and are going bare, because the cost is so high,” he said. “And they say, ‘You know, my home's destroyed, you know, I guess I'll just be out a lot of money.’ It's a really risky proposition.”

USA Today reported that the share of American homeowners without insurance has jumped from 5% to 12% since 2019.

There's always going to be a segment of people who live in an area that's so high risk that private insurance companies just can't operate there, he said.

So, state-level government plans try to fill in the gaps.

More Californians, for example, have turned to the FAIR Plan for basic property coverage.

The California FAIR Plan is an insurer of last resort and calls itself a “temporary safety net” for homeowners who can’t get traditional coverage.

The California FAIR Plan said its total exposure is $458 billion, up 61.3% over the last year.

Ragin said higher insurance premiums are partly because of inflation, especially the disproportionate inflation seen in construction costs. That’s impacting everyone, he said.

“But in a high-risk area, that's compounded by the fact that the frequency and severity of these losses is higher,” he said.

Insurance companies spread higher costs across the entire risk pool, he said. But people living in higher-risk areas still get stuck with higher bills.

“On the private market side, prices need to catch up to the risk or we need to lower the risk in order to get it to a place where there's equilibrium,” Ragin said.

He’s a proponent of mitigation efforts as a way of lowering the risks and, ultimately, the insurance costs.

But mitigation isn’t without its own costs or challenges.

And mitigation might not be a priority for budget-focused homeowners.

“You know, would you rather go on vacation or harden your home against wildfire?” Ragin said.

Without Investing in mitigation, without reducing the frequency and the severity the losses, things are just going to continue getting worse, he said.

Some mitigation efforts are costlier than others. It could cost more to raise your home above flood level, for example, than to clear brush to create a 5-foot defensible space as a guard against wildfires.

Insurance companies need to get better at pricing those mitigation efforts into their policies, Ragin said. But insurance companies also need to spend time and money to verify that homeowners actually completed the mitigation efforts they claim to have done.

Local governments can help, he said. For example, they could help elderly homeowners with brush removal.

“Mitigation is the piece that we really need to focus on now,” Ragin said. “Insurance can only do so much.”