N.Y.C. Admin. Code § 27-508: § 27-508 Maintenance and inspection.

(a) Maintenance. All signs, together with all supports, braces, guys, and anchors, shall be kept in good repair at all times, and when not adequately galvanized or constructed of corrosion-resistant materials, shall be painted periodically to prevent corrosion. It shall be the duty and responsibility of the owner or lessee of every sign to maintain the immediate premises occupied by the sign in a safe, clean, sanitary, and inoffensive condition and free and clear of all obnoxious substances.

(b) Annual inspection. Every sign for which a permit is required shall be inspected at least once in every calendar year.