Millions of Americans own homes that could flood at any moment. Many of them don’t have a clue. That’s what happened to Ralph Patricelli, a 57-year-old real estate agent who bought a house in North Carolina’s Outer Banks last summer. Last week, the four-bedroom waterfront vacation home he purchased with his sister for $550,000 was swept into the ocean. The house’s collapse was captured on video, which quickly went viral on Twitter. “I didn’t realize how vulnerable it was,” Patricelli said in an interview with the Washington Post.

Erosion, extreme weather, and sea-level rise have long threatened homes built on barrier islands like the one Patricelli’s house was located on. And yet Americans still buy homes in these areas with little to no knowledge of the risks and financial burdens they’re taking on. Studies show that 13 million Americans could become displaced by rising sea levels and $1 trillion worth of homes and commercial property could be inundated by the end of the century. Without intervention, more and more people, like Patricelli, will be left holding the deed to an empty lot or a severely damaged building. But there’s plenty that cities, states, and the federal government can do to prevent homebuyers from sinking money into properties that are destined to sink into the sea.

One major way to discourage homebuyers from buying flood-prone houses is to require sellers to disclose a property’s history of flooding to prospective buyers. But almost half of states don’t give homebuyers the right to this information. According to the Natural Resources Defense Council, 21 states have no flood disclosure requirements at all, and another five states have “inadequate” requirements.

Read the full article about rising sea levels by Zoya Teirstein at Grist.