Some homeowners are being told to clean their roof or they could lose their insurance.

"But it's definitely, you know, a shock after moving into a new home," homeowner Spenser Henry said.

The shock for Henry was a letter he got from his insurance company, Nationwide, telling him that his homeowners insurance policy was going to be canceled. The reason: plant growth on the roof of his home.

"I just said, 'I've never heard of this. This is ridiculous. What do we need to do to resolve it?' And he said, you basically need to get the moss removed, send them a picture and then they'll be able to reinstate our insurance," Henry said.

Henry and his wife had their roof washed.

"If you get to the point where you have moss growing on your roof, it has a filament root system and it can dig those roots in between the shingles," said Stephen Talbot, with Talbot's Power Washing.

Talbot said about 95% of his business right now is soft washing homes.

"Insurance companies have understood that organic growth on a house and on a roof can cause damage. And they don't want to cover an asset that hasn't been maintained properly," he said.

Sister station WGAL reached out to Nationwide Insurance, which confirmed it has been in contact with Henry but would not comment on the notice to cancel his insurance. Nationwide did tell the TV station that "moss and plant growth on a roof left untreated can cause damage to a home."

This kind of roof washing may be relatively new in the northeastern part of the U.S. But it's been happening for years now in the south, where the heat and humidity are much higher.

"The more shade cover you have, the dirtier, the more organic growth is going to accumulate on your roof, more quickly," Talbot said.

Dark, black streaks coming down your roof are an indication that you may have growth starting.

"When it gets to a higher level of growth, you start to see moss and algae actually growing on the shingles," Talbot said.

Roof washing not a trend yet

WGAL checked with several insurance agents who say that right now, roof washing is not a trend.

But if insurance carriers see a long-term benefit from it, homeowners may start seeing more requests to clean their roof.

What's the cost?

The home in this story had a whole house wash, which includes the roof and siding.

The approximate cost was $1,500, which has to be paid by the homeowner.

The average cost is 40 to 70 cents per square foot.

SONOMA COUNTY, Calif. — As the intensity and frequency of natural disasters increase, more homeowners are being left uninsured.

Charlie Martin is among those unprotected this wildfire season. Owner of Chalk Hill Ranch and Toby Lane Vineyards in Sonoma, County, California, Martin took over the family horse boarding operation 20 years ago.

"I work harder now than when I had a job," said Martin.

Up until 2017, the threat of wildfires was hardly on his radar.

“When the Tubbs Fire came, first big fire, thought well, this was a one-off. We were very lucky because it only burned 50 acres of the back of our ranch," said Martin. “The Kincade Fire, on the other hand, was a come to Jesus experience. We weren’t expecting it. The trauma, the emotion, everything that took place after that, it took a long time for us to handle.”

While his structures were spared, the 2019 fire scorched much of his ranch. Now, the threat is a part of life.

"I get up every morning, go out the door, and look for smoke," said Martin. “You never lose the thought of fire. Once you’ve experienced it, it’s part of you.”

But hyper-aware, his team is now better prepared to respond in an emergency. Working alongside the nonprofit NorCal Livestock Evac, they have an evacuation plan in place to move the 50 horses in their care to safety.

Yet, they feel more exposed now than ever.

“We had an insurance carrier for 40 years, never a claim. Not one claim. Well, we made our first claim, and they paid that claim, and then they immediately canceled," said Martin. “I haven’t been able to find insurance since.”

From 2018 to 2019, the number of policies that insurance companies decided not to renew increased 31% in the state. And rates are rising as wildfires grow more frequent and destructive. The same is happening in states like Florida and Louisiana, hit hard by hurricanes and other disasters.

"I actually had one company tell me they could insure me for five times the amount of premium that I had on my original policy, and I didn't take that because it was just astronomical," said Martin. “It’s like highway robbery. Where’s the deal? You don’t expect a deal, but you expect something at least fair.”

A new California report outlines "climate insurance" strategies. Mandated by state law, a working group of environmental advocates, researchers, and insurance experts was created to make policy recommendations to reduce the costs from wildfires, extreme heat, and flooding.

Among the recommendations, consider insurance policies for entire communities to guarantee that all residents have some degree of coverage.

It also recommends the state explore nature-based insurance solutions such as investments in wetlands and floodplains to reduce flood risk and the use of ecologically managed, open space buffers to protect from wildfires.

But until strategies become real-life solutions, more homeowners will find themselves uninsured—some relying on a higher power for protection.

“You can see this part of the hill was a very hot fire. But you see this bench here on the right? It didn’t touch that bench," Martin said, referencing a bench dedicated to his late mother. "So, we had to think she was sitting on that bench during the fire, saying, 'Not on my watch.'”

He says nearby homes on the market are going unsold.

“We’re just hoping something will turn around," said Martin. "I’m staying. If I don’t get insurance, where am I going to go?"