N.Y. Gen. Mun. Law § 120-N
Before taking any proceedings for the construction of any sewer or of any system of sewers or of any addition thereto or alteration thereof, such municipality or municipalities acting severally or jointly shall cause to be made a map and plan therefor, or an amendment of any map and plan previously approved, as the case may be, and shall submit the same to the state commissioner of health for his approval, and upon his approval the same shall be filed in his office. A copy of such map and plan or of any such amendment thereof shall also be filed in the office of the clerk of each such municipality. Any such map and plan shall include specifications of dimensions, connections and outlets or sewage disposal works and may also include any existing sewer which it shall be found feasible and proper to incorporate or include in the proposed system. No work of any kind shall be done on or for the construction, extension, reconstruction, removal or modification of any system of sewers or of any sewer thereof until a map and plan covering the entire system shall first have been duly approved and filed as above provided, and in the execution of the construction, extension, reconstruction, removal or modification of any system of sewers or of any sewer thereof no deviations from the plans as finally approved and filed shall be made until plans or descriptions adequately showing such deviations are first approved and filed as above provided. The state commissioner of health, in approving said map and plan or by a certificate supplementing any such approval, may authorize such municipality or municipalities to temporarily omit or defer the construction of any portion of any such sewer or system of sewers. A copy or copies of his approval or of any such supplemental certificate shall be certified to each such municipality and filed in the office of the clerk thereof.
N.Y. Gen. Mun. Law § 120-N