New federal flood maps and the city’s projections show more of the city will be at risk for severe damage from future storms and the city must prepare, Bloomberg said. “We’re not going to make the mistake of fighting the last war,” he said during a news conference unveiling the plans. Proposed rules are expected to reach the City Council this year.

Ten hospitals are vulnerable to flood in the event of another major storm under newly revised maps from the Federal Emergency Management Agency, according to the city’s report and recommendations. Projections by New York’s climate change experts place four regional trauma centers in floodplains during an extreme, or 100-year, storm by 2050, the report said.

Existing hospitals in flood zones would have until 2030 to meet some of the new requirements, including better protection for electrical equipment. NYU Langone Medical Center lost all power shortly after superstorm Sandy reached land last October, forcing an emergency evacuation of the Manhattan hospital. Other retrofitting will require backup air conditioning and connection points to hook up emergency boilers, chillers or generators, if needed.

Two hospitals owned by New York City—Bellevue Hospital Center and Coney Island Hospital—were severely damaged by floodwaters and evacuated after the storm.

New rules should not require retrofitting for elevators, emergency departments, laboratories or other critical functions to avoid “undue financial burden,” the report said. Bellevue’s elevators were disabled by the storm, and Alan Aviles, president of the city’s health system, said last November work would be done to protect elevators from future storms.

However, the city will seek to better protect Bellevue Hospital Center’s emergency department, though work will depend on funding, the report said.

The cost for hospitals to prepare, respond and rebuild from the storm—not counting lost revenue—is expected to total $2 billion, the report said.

More than two dozen nursing homes and other residential facilities were also forced to evacuate patients under emergency conditions, the report said, and future construction in flood zones would meet new electrical backup standards under proposed changes to the city’s construction codes, the report said.

Existing nursing homes in 100-year flood zones will also be required to meet new standards by 2030 to ensure access to power and water. Adult care homes will also have until 2030 to upgrade emergency electrical equipment. The city is expected to award $50 million in grants and loans to aid nursing homes and adult care providers to meet the new requirements.

Hospitals damaged by the storm remained closed for weeks or months, at significant expense and with added strain to the ones that remained open and absorbed their patients. The Veterans Affairs Department’s Manhattan hospital finally fully reopened in late May.

A sixth New York hospital, Long Beach (N.Y.) Medical Center has not yet recovered from significant flooding.