Hurricane Ida brought record — and catastrophic — rainfall to the city last September. More than six inches of rain fell in just a few hours.

The city’s infrastructure was inundated: 11 people drowned in basement apartments during the storm.

“We need a framework to legalize accessory dwelling units, which is like a broader term to define what a basement apartment is," said Marcel Negret, a senior planner with the Regional Plan Association.

The Regional Plan Association is an independent non-profit civic organization that works to improve the environment and quality of life in the Metropolitan tristate area.

The group released a report Monday looking at flood prevention measures for basement apartments in Central Queens. It focused on Jackson Heights, Woodside, Elmhurst, and Corona.

According to the report, there are 31,000 buildings in the area with below-grade basements, which property owners frequently convert into unlicensed apartments.

“Right now, basement apartments are illegal throughout the city," said Negret.

The report found that making them legal would help regulate and improve safety. It also finds Central Queens needs about 40 times more green infrastructure to better manage storm water. Currently, there are about three acres devoted to flood mitigation, including curbside rain gardens that help divert excess water.

“The intention of this was to capture the first inch of water," said Negret. "When there’s a more extreme event — like Ida, that was roughly 3.5 inches per hour of intensity — that’s more than the capacity that this kind of topology can handle." ​

Mayor Eric Adams has said he’s in favor of legalizing basement apartments, but needs support from the state legislature to make it happen.

A bill that would allow a program to bring unauthorized apartments up to code in the city died in Albany at the end of the legislative session.