Typically when we talk about “underwater” homes, we are generally referring to negative equity. But there is, of course, a more literal way a home can be underwater: Rising sea levels, and the flooding likely to come with them, could inundate millions of U.S. homes worth hundreds of billions of dollars.
In fact, based on our calculations, it may turn out that actual water poses almost as much of a problem for the housing market in the future as negative equity has in the past.
To quantify the impact of rising sea levels, we used maps released by the National Oceanic and Atmospheric Administration (NOAA) showing which parts of costal states will be underwater if sea levels rise by six feet. Why six feet? Some estimates suggest sea levels will rise that much by the year 2100 if climate change continues unchecked. Using that data in conjunction with our database of information on more than 100 million homes nationwide, we determined which properties were at risk of being submerged (at least their ground floors) in the next century or so and what they’re currently worth.
Nationwide, almost 1.9 million homes (or roughly 2 percent of all U.S. homes) – worth a combined $882 billion – are at risk of being underwater by 2100. And in some states, the fraction of properties at risk of being underwater is alarmingly high. More than 1 in 8 properties in Florida are in an area expected to be underwater if sea levels rise by six feet, representing more than $400 billion dollars in current housing value. In Hawaii, almost 1 in 10 homes are at risk.