N.Y. Tax Law § 1441
Notwithstanding any other provisions of law to the contrary, the town, acting through its town board, is hereby authorized and empowered to adopt a local law imposing in such town a tax on each conveyance of real property or interest therein where the consideration exceeds five hundred dollars, at the rate of two percent of the consideration for such conveyance. Provided, however, any such local law imposing, repealing or reimposing such tax shall be subject to a mandatory referendum pursuant to section twenty-three of the municipal home rule law. Notwithstanding the foregoing, prior to adoption of such local law, the town must establish a community preservation fund pursuant to section sixty-four-f of the town law. Revenues from such tax shall be deposited in such fund and may be used solely for the purposes of such fund. Such local law shall apply to any conveyance occurring on or after the first day of a month to be designated by such town board, which is not less than sixty days after the enactment of such local law, but shall not apply to conveyances made on or after such date pursuant to binding written contracts entered into prior to such date, provided that the date of execution of such contract is confirmed by independent evidence such as the recording of the contract, payment of a deposit or other facts and circumstances as determined by the treasurer.
N.Y. Tax Law § 1441