N.Y.C. Admin. Code § 27-493: § 27-493 Safety precautions.

(a) No overhead electrical conductors shall be installed within fifteen feet of any swimming pool. All metal fences, enclosures, or railings that might become electrically charged as a result of contact with broken overhead conductors or from any other cause near, or adjacent to, a swimming pool shall be grounded in accordance with the provisions of lightning protection in the electrical code of the city of New York.

(b) Every outdoor swimming pool, fish pond, or other pool greater than eighteen inches deep at any point shall be protected by an enclosure, barrier or other means adequate to make such pool inaccessible to small children which including gates thereto shall be at least four feet high above the adjacent ground. All gates shall be self-latching with latches located at least four feet high above the ground or otherwise made inaccessible to small children from the outside.