32 Pa. Stat. § 637
It shall be the duty of the board upon receipt of an application under section six of the act, to make such investigation as may be necessary, including a search of the water acquisition record, to determine whether the approval of the application will affect water rights theretofore confirmed or approved, or water rights at that time the subject of application to the board, or water rights for the acquisition of which a permit shall theretofore have been issued. In case of apparent conflict of interests, the investigation shall include and consider the extent of the conservation development and use to the best advantage of existing sources of water supply. In case of established conflict of interests, the board, after receipt of an application or at any time or from time to time, shall have the power to issue, modify or impose conditions in permits or confirmed claims for, or to the acquisition of, water rights theretofore or thereupon issued when deemed necessary by the board in the public interest, and it shall be the duty of the board to issue and it shall issue all such permits and modification and conditioning orders as the public interest shall require.
However, if the board finds that the proposed new source or additional supply will not conflict with the rights to such water or to water rights held by any other public water supply agency which are reasonably necessary for its present purposes or future needs, and that the water or the water rights proposed to be acquired are reasonably necessary for the present purposes and future needs of the public water supply agency making application, that the taking of said water or the exercise of said water rights will not interfere with navigation, jeopardize public safety, or cause substantial injury to the Commonwealth, then, and in that case, the board shall approve the application and shall issue a permit therefor.
32 P.S. § 637