N.Y.C. Admin. Code § 25-311: § 25-311 Maintenance and repair of improvements.

a. Every person in charge of an improvement on a landmark site or in an historic district shall keep in good repair (1) all of the exterior portions of such improvement and (2) all interior portions thereof which, if not so maintained, may cause or tend to cause the exterior portions of such improvement to deteriorate, decay or become damaged or otherwise to fall into a state of disrepair.

b. Every person in charge of an improvement containing an interior landmark shall keep in good repair (1) all portions of such interior landmark and (2) all other portions of the improvement which, if not so maintained, may cause or tend to cause the interior landmark contained in such improvement to deteriorate, decay or become damaged or otherwise fall into a state of disrepair.

c. Every person in charge of a scenic landmark shall keep in good repair all portions thereof.

d. The provisions of this section shall be in addition to all other provisions of law requiring any such improvement to be kept in good repair.