N.Y. Gen. Mun. Law § 119

§ 119. Construction and development of excess sewage capacity. Any\ncity or village, any county on behalf of a county sewer district and any\ntown on behalf of a town sewer district or sewage disposal district may,\nin addition to all other powers possessed with respect to the\nconstruction and development of sewage facilities, provide for the\nconstruction and development of capacity in excess of its own needs for\nconveyance, treatment and disposal of sewage for the purpose of\nconveying, treating and disposing of sewage of another public\ncorporation or improvement district, and, any provision of law to the\ncontrary notwithstanding, may contract indebtedness for such purpose.\nThe term "public corporation" as used in this article shall mean a\npublic corporation as defined in the general corporation law.\n