The real estate industry is pressuring Zillow and other sites to nix extreme weather risk data buyers have come to rely on

By Ella Nilsen, CNN

(CNN) — Zillow, the nation’s largest real estate listing website, has removed extreme weather risk data meant to help buyers figure out if the biggest purchase of their life is particularly susceptible to floods, high winds or wildfires.

Now, other major real estate listing websites are facing pressure to do the same.

That pressure is coming from the California Regional Multiple Listing Service, which operates one of the largest private databases of home listings in the country — essential to Zillow’s business model.

Out of concern that it has impacted home sales, the California group is questioning the accuracy of some climate change-related data compiled by risk modeling company First Street. That company creates current and future risk scores for climate change-fueled disasters like wildfires, coastal and rainstorm flooding, high winds, extreme heat and air quality, which are displayed on real estate websites including Redfin, Realtor.com and, until recently, Zillow.

Art Carter, the CEO of the California Regional Multiple Listing Service, said in a statement that First Street’s “future predictions ended up being very wrong” on flooding in California.

The group became suspicious after seeing home listings with a high projected chance of near-future flooding “despite having no flood activity for decades,” Carter said. In addition to Zillow, Carter’s group has also asked Realtor.com, Redfin, and Homes.com to remove First Street’s predictive numbers and flood layer maps from their listings.

“The display of a probability of a specific home flooding this year, or in the next five years, can have a significant impact on the perceived desirability to purchase that property,” he added.

There’s evidence the information is impacting home sales. Zillow’s analysis of its own data found that homes listed in June 2024 with a high flood risk were less likely to sell by March 2025 than those with a low flood risk. Just 52% of the high-risk homes sold compared to 71% of the low-risk homes.

And First Street says its data is more accurate than limited federal data like FEMA flood maps.

First Street founder and CEO Matthew Eby said his company’s maps outperformed California’s state maps during January’s devastating Los Angeles wildfires, identifying more than 90% of the homes that ultimately burned in the Eaton Fire as being at “severe” or “extreme” risk to wildfire. California’s own analysis put just 21% of the same homes in a “very high” fire hazard zone. The state has initiated changes to those maps as a result.

“We take accuracy very seriously, and the data speaks for itself,” Eby told CNN in an email. “When buyers lack access to clear climate-risk information, they make the biggest financial decision of their lives while flying blind.”

A Zillow spokesperson said the site “updated our climate risk product experience to adhere to varying MLS requirements and maintain a consistent experience for all consumers.” The spokesperson added the company made the policy across the country for “a consistent experience on our site.”

The Zillow spokesperson said First Street data is still linked to its listings, although far less visibly than the data displayed on Redfin and Realtor.com. But each company may take different actions.

“Redfin will continue to provide the best possible estimates of the risks of fires, floods, and storms,” Redfin spokesperson Angela Cherry told CNN in a statement. “Every home is different and no model is perfect, so if sellers believe the information is inaccurate for their listing, they can ask Redfin to remove it.”

Realtor.com spokesperson Sara Wiskerchen said “we are working with CRMLS and our data providers to look into the issues surfaced.”

There’s no easy answer because First Street, and similar groups doing data and modeling for climate risk, are private companies, said Oriana Chegwidden, a research scientist at the nonprofit CarbonPlan.

Even though Eby told CNN that his company’s models “are built on transparent, peer-reviewed science,” independent scientists say it’s hard to verify the accuracy of a private company whose data is not available to the public. First Street has built its public image by sharing maps and modeling results with journalists, including those at CNN. But the company’s business model is based on selling that data to banks, corporations, asset managers and real estate companies. To make the business work, it — and other companies like it — keep a tight lid on how their models function.

And while models that predict climate change on a global level have largely been consistent and accurate, Chegwidden conducted a study in 2024 that found risk modeling can have wide-ranging variations at an individual property level. Many in the climate risk industry also didn’t want to open their models to inspection; of nine companies she and other researchers contacted, only two agreed to participate in the study. (First Street did not participate.)

That makes it hard to determine exactly how accurate the modeling — and climate risk predictions — actually are.

“Yes, it’s hard to predict the future. Yes, people are doing it,” Chegwidden said. “It’s so important for that science to be transparent, because that science is going to influence whether or not someone can get insurance (or) whether or not someone can sell their home.”

But such a public database does not yet exist, and Eby said having the private data accessible to homebuyers is “essential to protecting consumers and preventing lifelong financial consequences.”

The pressure from real estate groups to remove the data “didn’t arise when housing markets were roaring and inventory was plentiful,” Eby said. “It’s happening now, during one of the toughest real-estate environments in decades. All of that adds pressure to close sales however possible. Climate risk data didn’t suddenly become inconvenient; it became harder to ignore in a stressed market.”

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