A New York City Council member is trying to give the city a heads-up on vacant building sales.

Councilman Ben Kallos plans to introduce legislation on Thursday that would require real estate brokers, realtors and listing agents to notify the city 30 days before a vacant property — including empty lots and unoccupied buildings — of 20,000 square feet or more goes up for sale, Commercial Observer has learned.

Kallos said the bill will bring the city in the loop on transactions, giving it the first right of refusal on vacant properties to allow it to build more schools, firehouses and other municipal buildings. 

“In my district, which is the Upper East Side, we have three gigantic vacant spaces,” Kallos told CO. “I’m trying to build more pre-K sites, and more schools [and] firehouses … It’s clear to me that it is a bad thing that real estate isn’t getting into the hands of the government [and] public-private partnerships aren’t happening frequently.”