As home insurance becomes increasingly unaffordable or unavailable for millions of Californians, a homeowner has filed a proposed class-action suit accusing Liberty Mutual Insurance of canceling her policy and others for nonexistent defects based on unreliable aerial photography.

“Driven by a desire to maximize profits, property casualty insurance companies, including (Liberty Mutual), have engaged in a troubling trend of dropping California homeowners’ insurance policies like flies,” lawyers for Maria Badin, a 31-year homeowner in the San Diego County community of Poway, said in the lawsuit, filed in the county’s Superior Court.

“California homeowners, who have dutifully paid their premiums for years, have been, and are, being blindsided by (Liberty’s) nonrenewal notices informing them their policy will not continue — for stated reasons that are demonstratively false.”

The suit seeks unspecified damages for Badin and other policy-holders and a court order requiring Liberty Mutual to change its practices.

Attorney Michelle Meyers said Thursday the proposed class-action would include at least the 17,000 policy-holders who lost their fire insurance coverage when a Liberty subsidiary refused to renew them late last year. The company did not cite aerial photographs for the cancellations and said instead that its technology could no longer oversee the policies, but Meyers said the lawsuit challenges all such unjustified non-renewals.

“They’ve insured these homes for years with the same risks they had at the time,” Meyers said. “It seems pretty clear that (the non-renewal decision) was done for money,” the higher premiums that can be charged for new policies, she said.

State Insurance Commissioner Ricardo Lara has ordered insurers to match at least 85% of their California market share in areas that are at a high risk of wildfires, a change that will likely lead to higher costs for consumers.

Liberty Mutual spokesperson Gregory Kessler said the company does not comment on lawsuits.

In the last few years, major insurers in California have refused to renew many homeowners’ policies, citing dangers or defects the companies had not previously reported.

Often, as in Badin’s case, insurers say they have conducted aerial inspections and found conditions that make the home more vulnerable to damage. Some homeowners have discovered that the photographs, taken from air levels of 4,000 to 10,000 feet, may have mistaken neighbors’ homes for theirs.

Badin said Liberty Mutual notified her last August that her policy, in effect since 1993, was being canceled in November because an aerial inspection had revealed “algae/mildew/mold/moss” on the roof of her home. 

The company sent her a long-distance aerial photo of the roof, which showed no signs of algae, mildew or any other contaminant, Badin’s lawyers said in their lawsuit, which included the photo. She contacted an independent roofing company that took a close-up photo, also attached to the suit, and told her the roof was “in incredible shape,” her lawyers said.

Liberty Mutual stood by its conclusion and refused to renew Badin’s policy in November, the suit said. It said she has obtained a new policy, with less coverage and higher premiums, from the FAIR Plan, a state-regulated association of major insurance companies that provides coverage in areas that individual insurers are reluctant or unwilling to cover.

Reach Bob Egelko: begelko@sfchronicle.com; X: @BobEgelko