All franchises heretofore granted are recognized as contracts between the City of Pleasanton and the grantee, and the contractual rights as contained in any such franchise shall not be impaired by the provisions of this Charter, except that the power of the City of Pleasanton to exercise the right of eminent domain in the acquisition of utility property is in all things reserved, and except the general power of the city heretofore existing and herein provided for to regulate the rates and services of a grantee which shall include the right to require proper and adequate extension of the plant and service and the maintenance of the plant and fixtures at the highest reasonable standard of efficiency. Every public utility franchise hereafter granted shall be held subject to all the terms and conditions contained in the various sections of this Article whether or not such terms are specifically mentioned in the franchise. Nothing in this Charter shall operate to limit in any way, as specifically stated, the discretion of the City Council or electors of the City in imposing terms and conditions as may be reasonable in connection with any franchise grant.