Americans take a lot of factors into consideration before buying a new home: Is it in a good school district, how many bathrooms does it have, does it have good bones? New research shows people should also be asking about their home’s flood history, because the wrong answer could be costly. 

A new report from the Natural Resources Defense Council, or NRDC, shows that people who buy homes with a history of flooding in three U.S. states — North Carolina, New Jersey, and New York — can expect to pay tens of thousands more dollars in flood damages over the course of their mortgage than the average homeowner. 

The solution for prospective homebuyers appears to be straightforward: Make sure you take a look at the property’s flood history before signing your name on the dotted line. But in most U.S. states, including North Carolina and New Jersey, state laws don’t require sellers to disclose whether a home has flooded in the past. In New York, such a requirement exists, but sellers can bypass it by paying a $500 fee. 

Millions of Americans are likely making what is typically the biggest and most important purchase of their lives without the relevant information they need to make an informed decision. “It can be financially ruinous,” Joel Scata, an attorney at NRDC, told Grist. 

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The premise that a home that has flooded in the past could flood again and cost a homeowner money down the line isn’t particularly novel, Scata pointed out. But the report, conducted by the consulting firm Millman, highlights just how much money, on average, flood-prone homes cost Americans. The study looked at those costs as they stand right now and what they’ll look like in the future as the planet continues to warm and the impacts of climate change worsen. 

Millman analyzed all the homes sold in North Carolina, New Jersey, and New York in 2021 and found that 6.6 percent of them, 28,826 homes, had been previously flooded. Millman used Federal Emergency Management Agency data and independent flood risk models to determine past and future flooding for these properties. The report found that, if the climate were to stay exactly the same as it is today, the average individual homeowner of a previously flooded home would expect to pay roughly $18,000 in flood-related damages over the course of a 15-year mortgage in North Carolina, $25,000 in New Jersey, and $47,000 in New York.

In total, the average total annual cost of damages for all of the flood-prone properties in the three states surveyed by Millman works out to $16 million in North Carolina, $18 million in New Jersey, and $23 million in New York. And that’s just under current climate conditions.

The report found that the costs of flooding rise significantly under a medium-emissions climate change scenario — one in which the world limits its emissions to some extent instead of continuing on business as usual. The average holder of a 15-year mortgage can expect to incur roughly $22,000 in flood damages in North Carolina, $32,000 in New Jersey, and $60,000 in New York over the course of their mortgage. Those numbers double over the course of a 30-year mortgage.

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“What was really surprising about the report was just the amount of money that a homeowner could pay out of pocket over the course of their mortgage because of the high risk of those properties to floods,” Scata said. “Especially when you factor in the impacts of climate change.” Although mortgage holders for some properties are required to purchase flood insurance, the requirements are based on outdated flood maps that omit many vulnerable areas. According to the University of Pennsylvania’s Risk Management and Decision Processes Center, just 30 percent of homes in the nation’s highest-risk areas are covered by flood insurance.

Twenty-one states have no laws in place requiring sellers to disclose whether the property they are selling has flooded or sustained water damage before, and if it is likely to flood again. The Biden administration recently proposed establishing a national flood disclosure law that would require sellers in all U.S. states to disclose a property’s flood history to potential buyers, but that reform would have to be approved by Congress, and there’s no guarantee that that’ll happen anytime soon. 

“Having a nationwide uniform disclosure law would ensure that there would be a baseline that all states have to meet in terms of the information they require sellers to provide to homebuyers,” Scata said. “Seeing that move forward would be really helpful.”

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