(Bloomberg) — First Street Foundation, a nonprofit agency, is making accurate climate change-adjusted flood scores available for every property in the U.S. today. There are government-produced maps showing 8.7 million homes and properties at significant flood risk — and it turns out those may have underestimated the amount of real estate at risk by 67%. Or, in other words, an additional 6 million properties face a significant risk of flood.

Before these individual property scores were available, there was no easy way for your average homeowner or buyer to understand the flood risk associated with specific properties. That's particularly problematic because climate change is causing flood risk to increase; there are more extreme rain events and coastal flooding than there used to be.