The reservoir and appurtenant works shall be kept in safe, sanitary and serviceable condition and to this end shall be repaired, remodeled or additional work done thereon at the request of the applicant or as required by the department. All such work shall be done by the department at the expense of the applicant. If the applicant shall at any time determine that its needs for an additional supply of water require the enlargement of the reservoir in order that a greater quantity of water can be stored therein or drawn therefrom, a new water supply application shall be made to the department asking for approval of the desired modifications of the original plans.
New York Legal Code