N.Y. Private Housing Finance Law § 404
1. No such loan shall be made by a municipality to an owner of an existing multiple dwelling unless the owner of such multiple dwelling shall covenant in writing that so long as any part of such loan remains unpaid, any exemption and abatement from taxation on the property resulting from the installations, alterations or improvements made with such loan remains in effect or for a period of at least ten years from the occupancy date, whichever is the later: