Zillow added climate risk data to its for-sale listings. Not everyone in the real estate game is happy.

“Location, location, location!” screams the Zillow listing. This Revere home — a four-bedroom with second-floor water views for less than $500,000 — is just waiting for the right buyer.

Or how about the two-bedroom, two-bath in Haverhill, located near a “serene riverfront” and boasting a stunning yellow Southern pine ceiling? Or what about this cozy three-bedroom seasonal home in Humarock — a short stroll from the river and the beach, “an oasis for relaxation and fun”?

They all sound like the kind of homes people dream about owning — or, maybe, are a nightmare to own, if you read on to see what else Zillow has to say about the properties: they all are at severe or extreme risk of flooding, based on a new climate risk assessment the popular real estate site has recently added to its listing of properties for sale.

The risk scores affect an enormous number of properties in Massachusetts: more than 150,000, and nationwide, nearly 13 percent of new listings on Zillow are now assessed as being at major risk of flooding.

“That’s the reality of climate change to housing, and that’s why this information is so important,” said Skylar Olsen, chief economist at Zillow.

That reality was brutally enforced over the past few weeks as hurricanes Helene and Milton inflicted billions of dollars of damage to homes and properties across a substantial part of the Southeast.

Zillow is relying on data from First Street, the climate risk financial modeling firm, using a 1-10 score for the risk of flood, fire, wind, poor air quality, and heat. With sea levels around coastal Massachusetts 14 inches higher than a century ago, the biggest risk to properties appears to be flooding, both along the coast and inland near rivers.

This type of information, which incorporates historic flood data and layers on projections for how climate change will increase sea levels and precipitation, has been available for a few years, but it was used primarily by institutional investors, said Jeremy Porter, head of climate implications research at First Street. “Our goal was to make sure everybody can understand the climate risk,” he said. Other websites, including Redfin and Realtor.com, have made climate risk data from First Street available in recent years, but the addition of Zillow — the most popular real estate website — marks a major shift in saturating the market with this information.

The flooding projections are based on data from the Federal Emergency Management Agency, as well as NASA’s global climate models. The analysis shown on Zillow reflects a future that roughly follows the trajectory we are currently on, in which greenhouse gas emissions continue and the planet warms from 4.3 to 5.4 degrees Fahrenheit above preindustrial times by the end of the century.

In recent years, as the consequences of extreme weather have become more intense, home buyers are increasingly asking about climate risks, said Theresa Hatton, chief executive of the Massachusetts Association of Realtors.

The new risk scores on Zillow will make buyers “more cautious and cognitive about the risks associated with these properties,” Hatton said, and more likely to make sure they have the right insurance if they decide to go ahead with a property that might come with a heightened risk.

But not everyone in the real estate game is happy.

“It’s putting thoughts in people’s minds about my listing that normally wouldn’t be there,” said Dorothy McLaughlin, a Hingham-based real estate agent representing the seller of the Revere four-bedroom. The property is several blocks in from the shoreline and behind MBTA tracks and already requires flood insurance. But in McLaughlin’s opinion, it’s unlikely that the water would ever reach the home.

“How do you know what the climate is going to be in 35 years?” she said.

That’s precisely what the data is trying to project, though. For that home, the Zillow analysis gives just a 4 percent likelihood of flooding this year. But with rising seas and stronger storms, that risk climbs to 72 percent in the next 15 years and 97 percent in the next 30.

Over in Scituate, real estate agent Andrea Campbell said the risk score also doesn’t give the full picture. Zillow’s scores are based on models, not by home inspections. “What they don’t take into consideration is the actual structure that’s on the property,” she said, noting that for the listing she had, Zillow assigned a flood risk of 9 out of 10, but is built on 55 concrete posts. “Elevation means a great deal when it comes to flooding.”

Emily Norton, executive director of the Charles River Watershed Association, said the Zillow listings are a good start, but noted the state has far to go when it comes to addressing flood risks. Massachusetts is one of just 14 states — and the only state in New England — that do not require any disclosures about the risk of flooding when a property is sold, according to an analysis by the Natural Resources Defense Council.

“There’s disclosure about lead, there’s disclosure about other things. Why isn’t there disclosure about flooding?” said Norton. As such, it’s possible that a buyer in Massachusetts could sign a mortgage on a home that routinely floods, and will likely flood even more as climate change progresses, without realizing it.

For now, the data available on Zillow will be “beneficial for the future generations,” said Evan Blaustein, a Brookline-based agent who encourages his clients to think about ways to minimize carbon emissions generated by their new property.

While Zillow’s new ratings are useful, he said, they could also make it tricky for sellers whose properties have suddenly been tagged as high-risk. “That’s obviously a concern that a lot of homeowners are going to have.”

There’s also another reality that prospective buyers are contending with in Massachusetts: a housing shortage.

“There’s not enough housing for this to have a significant impact,” said Hatton, of the Massachusetts Association of Realtors. “What it’s going to do, is it’s just going to have buyers be more cautious and cognitive about the risks associated with these properties.”

That means going into a sale knowing up front that some changes will have to be made, or that extra insurance may be required. That, too, can be tricky. While experts say it’s unlikely that insurers will flee risky parts of Massachusetts in the same way they have in California or Florida, premiums are expected to reflect the increased risks of climate change. And some companies may decline flood insurance for properties deemed too risky.

For Rebecca Kleppe, whose two-bedroom condo in Haverhill notched a 10/10 score for extreme risk of flooding, it’s all a bit of a head-scratcher. When she bought her condo in 2006, she opted for one that was nearly a block away from the Merrimack River, knowing that other condos in the development that were closer to the river had flooded in recent years. She said she hasn’t had any problems, though she was required to buy extra insurance.

“This just doesn’t ring true to me,” she said.

But the good news is, she’s no longer worried about Zillow scores scaring off a prospective buyer: “I’ve already accepted an offer.”