FEMA will be revising New York City’s flood maps, it announced in a release yesterday (October 17). Now, these maps will include future flood zones that are a result of climate change and a rise in sea level. The new maps will take three to four years to finalize.

These maps determine who is required to purchase flood insurance for their homes, a major concern when FEMA first revised the maps last year. The statement explains:

Revised flood maps will provide New York City residents with more precise current flood risk data, in addition to providing a new map product reflecting future conditions that account for climate change. The innovative revisions will assist New York City in making coastlines more resilient and climate-ready, while ensuring homeowners are not required to purchase more insurance than their current flood risk requires.

Mayor Bill de Blasio’s administration appealed the original maps in 2015 after FEMA placed 35,000 extra homes and buildings into “highest flood risk areas,” locations that are considered 100-year floodplains. This would have hurt thousands of low- and middle-income New Yorkers, WNYC reports.

“We are building a stronger, more resilient city to confront climate change. Our city needs precise flood maps that reflect real risks, both today and years from now—and we have to do that fairly. We will work closely with FEMA to ensure New Yorkers in the floodplain are prepared, and that the tools to make them more resilient, like flood insurance, remain available and affordable,” said Mayor Bill de Blasio in the FEMA press release.

However, in other parts of the country, areas outside high-risk flood zones have recently been hit by natural disasters. When storms flooded Louisiana in August, FEMA refused to revise the state’s flood maps, reported The Advocate, even though flooded areas were outside the designated flood zone. North Carolina’s Hurricane Floyd in 1999 counted as a 500-year flood event, reported ThinkProgress. There’s still a chance Hurricane Matthew may be categorized the same way, as flooding is ongoing in the state. Only 100-year flood zones are required to have flood insurance, which can be a preventative blessing or a financial burden depending on household income.

(H/t WNYC, The Advocate, ThinkProgress)