N.Y. Pub. Health Law § 1106
Nothing contained in this chapter shall extend the sanitary control of the board of water supply of the city of New York, beyond the sources of potable water supply, tributary to the Catskill and Delaware aqueducts; and the powers granted by this chapter to the board of water supply of the city of New York shall cease at the time of the transference of the jurisdiction over the source of water supply, by the board of water supply to the commissioner of environmental protection of the city of New York; and at no time shall the commissioner of environmental protection of the city of New York and the board of water supply of said city have or exercise concurrent powers or sanitary control over any source of potable water supply tributary to the Catskill or Delaware aqueduct.
N.Y. Pub. Health Law § 1106