Climate change is predicted to drive increasing sea level rise across the country in the coming decades — and thousands of families in the Bay Area are unprepared for the flooding impacts.

The ABC7 data journalism team analyzed data from the First Street Foundation, a nonprofit science and research group that studies climate risk data. It found more than 300,000 homes in the Bay Area have an 80% chance of flooding over the next 30 years and nearly 90% of those homeowners may not have flood insurance.

LeAnn McGinley lives a few hundred feet away from a newly completed section of sea wall in Foster City. The multimillion-dollar upgrade means LeAnn and her neighbors will not be required to purchase flood insurance, which can run hundreds of dollars or more.

“I am retired and of course, that’s a fixed income,” McGinley said. “Right now I would probably be alright, tapping into savings but no one wants to do that for their daily expenses.”

While McGinley’s area has a potential solution to future flooding, balancing the cost of flood protection and flood insurance could be an increasingly expensive challenge for other communities around the Bay.

Amy Bach, the director of the consumer nonprofit United Policyholders, said not only will more people need flood insurance in the coming years, but the current lack of insurance protections for many is an issue in the present day.

“Last winter, when California saw those deluges, a lot of people had losses and damage,” Bach said. “There was a lot of eye-opening of wow, I didn’t realize that I could flood.”

Marin County has the highest percentage of properties that have a major risk of flooding within the next 30 years. About 35% of properties, or over 33,000 homes, are at risk. Almost 37,000 of those homes may not be covered by flood insurance. Within the county, the census tract with the highest risk has a 92% chance of flooding over the next three decades.

In San Mateo County, where 20% of properties — over 42,000 homes — are at a major risk in the future, there are several census tracts bordering the San Francisco Bay with over a 90% risk. Out of the properties in the county at risk, almost 38,000 may not be covered by flood insurance. Over 210,000 properties overall may not currently have flood insurance.

Bach said the numbers reflect a growing strain on the state’s insurance system from natural disasters, including floods, wildfires and earthquakes, with the current patchwork of public and private coverage struggling to spread risk.

“I think that the way things are going, we are going to have to have some kind of a federal disaster insurance program, you know,” Bach said. “Just like we created the Affordable Care Act, and we said, these are the essential benefits that an insurer must provide, an insurer cannot reject somebody who has a pre-existing condition, I think we’re going to have to get there with property in the sense that we’re all in this together, right?”

Last month Gov. Gavin Newsom signed an executive order designed to stabilize the state’s property insurance market, potentially allowing insurers to factor the future risk from climate change into their rates.

While the complicated market continues to shake itself out, McGinley is grateful for a bit of breathing room from the new sea wall, at least where flood insurance is concerned.

“I was originally for the project and even more so now,” McGinley said. “I think the future is very not only for me and my family but for other generations, and this is important for that protection.”