A quiet decision by the nation’s largest home-listing authority may soon determine who’s legally responsible for warning homebuyers about climate risk.
Last month, the California Regional Multiple Listing Service — the dominant database used by real estate agents in the country’s largest housing market — pressured Zillow to remove climate-risk scores produced by First Street, an independent research group whose flood and wildfire models are widely used by insurers, banks and public agencies. Zillow depends on CRMLS’ feed for individual home and rental listings, so it quickly complied. Overnight, climate-risk information disappeared not only from Zillow’s California listings but from every home listed across its national platform.
CRMLS framed this as a dispute about scientific accuracy. But the more significant impact falls on real estate agents.
Under long-standing principles of real estate law and material fact disclosure, agents have a duty to disclose known risks that could materially affect a buyer’s decision. When an agent or broker is aware — or reasonably should be aware — of credible hazard data for a property, the information can’t be ignored simply because it vanishes from a consumer-facing site.
By disputing these independent risk models and urging widely used real estate platforms to suppress them, CRMLS has effectively failed to shield agents and brokers from bearing responsibility. Instead, it may actually have done the opposite — making the agents who rely on it legally responsible for disclosures without the support of standardized, third-party transparency tools.
When a buyer later discovers that a property faces severe flood or wildfire risk that had been modeled and made publicly available and considers litigation, they’re likely to focus on whether their agent or broker fulfilled their duty to disclose information at the time of sale. They will also no doubt ask why the dominant listing authority intervened to eliminate these risk warnings while positioning itself as an arbiter of their accuracy.
The National Assn. of Realtors recognizes this tension. Its own guidance warns agents and brokers against positioning themselves as climate science authorities, and instead urges transparent reliance on reputable third-party risk data. CRMLS’ campaign to dismiss independent models cuts directly against that risk management approach, leaving agents and brokers more exposed to liability, not less.
Recent events underscore why third-party data is essential. After January’s Eaton fire in Altadena, a Los Angeles Times investigation reported that California’s official wildfire hazard maps failed to identify many of the neighborhoods that ultimately burned, capturing only about 21% of the homes at risk. By contrast, First Street’s independent models had successfully flagged about 94% of the destroyed homes as facing “severe” or “extreme” risk.
Accurate flood-risk mapping tells a similar story. Most Americans assume risk exists only within the Federal Emergency Management Agency’s Special Flood Hazard Areas. However, FEMA acknowledges that a majority of flood-insurance claims come from outside those areas. The agency also concedes that more than 70% of U.S. flood maps are outdated, with many reflecting assumptions from the 1970s and ’80s. Investigative reporting has repeatedly documented events where FEMA maps understated dangers while independent models accurately warned of flood exposure.
CRMLS objects to the disclosure of these risk scores based on probabilistic modeling. Yet probability-based forecasting is the backbone of insurance pricing, underwriting and virtually every other major financial risk system in America. Courts demand neither mathematical perfection nor deterministic guarantees. They require reasonable, evidence-based disclosure when material risks are known.
Modern climate-risk modeling meets that standard. First Street’s methodologies are transparent, peer reviewed and repeatedly validated against real-world losses, which is why banks, insurers, engineering firms and federal agencies all rely on these projections to deploy capital and manage public safety planning.
The practical effect of suppressing public risk disclosures is not legal insulation for real estate agents and brokers. It may be the opposite. Without standardized third-party data presented directly to buyers, agents may carry greater responsibility for communicating these risks themselves. When hazards later materialize, the question will not be whether Zillow showed a risk score. The question will be whether the agent discharged their professional duty to inform the buyer of known and credible risks to the property.
Zillow’s role also raises questions. The company depends on CRMLS’ data feed and access to its California listings. But if CRMLS’ objections were limited to California, why did Zillow remove climate-risk scores across the country? What began as a regional dispute resulted in a nationwide rollback of scientific data that consumers had relied on for years.
CRMLS already suggested that it intends to pressure other major real estate platforms, including Redfin, Realtor.com and Homes.com, to follow suit. Should these platforms comply, real estate agents could find themselves selling homes in a market where a single influential muliple listing service effectively dictates which risk disclosures are publicly available across the national marketplace. And if those suppressed risks materialize in damaged or destroyed homes, as is often the case, the liability trail will be long and clear.
Dave Jones is the director of the Climate Risk Initiative at UC Berkeley and a former California insurance commissioner.
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