The Federal Emergency Management Agency is redrawing New York City’s flood maps for the first time in more than 30 years, and it could have a major impact on how developers build in the city.

Because of its vast coastline and expanding waterfront development, New York has more people living in high-risk flood zones than any other city in the United States, the New York Times reports.

More than 80% of the city’s buildings were built before the current flood maps were put in place, according to the Times, and owners of properties that are in the new high-risk zones may be on the hook for increased insurance premiums and extensive modifications. FEMA last mapped the city in 1983, with only small alterations since.

The 2013 preliminary maps the agency proposed doubled the area of flood zones, but the city successfully challenged the scientific assumptions on which the maps were based. New York City and the agency are set to begin formal discussions on the flood maps in the coming weeks, according to the Times.

“Sandy may not happen again like it did,” FEMA's acting chief of the risk analysis branch in New York, J. Andrew Martin, told the Times. “But there will be something very similar, and it’s not that far off.”

The 2012 storm caused $19B in damage to the city, and architects have previously told Bisnow that protecting against future weather events will fall into the hands of individual owners.

Eight years ago, property within the 100-year flood plain was worth $58.7B, the Times notes, citing a report from the city comptroller. By 2014, it had spiked to $129.1B.

Some developers are already building with weather events in mind.

At Brooklyn’s Greenpoint Landing, a massive, 22-acre development site that will ultimately feature 5,500 apartments and 11 buildings, developers Brookfield and Park Tower Group designed its esplanade park with material that can withstand storm surges and high winds.

At 11 Beach St. in Tribeca — a luxury development from Ziel Feldman’s HFZ Capital Group — a corner of the building would fall into the new zones, subjecting the building to FEMA regulations. The architects removed the corner from the design, according to the Times.

“If you bake the retrofit into your costs now, it’s a marginal investment, and it protects your property and, more importantly, the people who will live there,” said Roland Lewis, the president and CEO of the Waterfront Alliance, a group aimed at protecting the city’s shorelines.