(a) As a necessary aid to the conservation, control, preservation, purification, and distribution of surface water and groundwater within the authority, the authority may, within the San Antonio River Basin:
(1) construct, own, operate, maintain, or otherwise provide sewage gathering, treatment, and disposal services, including solid waste disposal services;
(2) charge for services described by Subdivision (1); and
(3) make contracts with counties, municipalities, and others regarding services described by Subdivision (1) or charges described by Subdivision (2).
(b) The authority may not exercise the powers described by Subsection (a) in Kerr, Real, or Bandera County unless consented to by a majority vote of the commissioners court of that county.