N.Y. General City Law § 52

§ 52. Notice, how served; proceedings when violated not removed. Such\nnotice may be served personally or by mail, and if by mail it may be\naddressed to such master plumber at the address registered by him, but\nthe failure of a master plumber to register will relieve the official or\nboard who or which appoints the plumbing inspector from the requirement\nof giving notice of violation. Unless the violation is removed within\nthree days after the day of serving or mailing such notice, exclusive of\nthe day of serving or mailing, the official or board who or which\nappoints the plumbing inspector may proceed according to law.\n