However, the authority may fix rates and charges for services of its sewer or sewage disposal system sufficient to pay all or any part of the cost of operating and maintaining its water system, including distribution and disposal, and all or any part of the principal of or the interest on the revenue bonds issued for such water system, and to pledge any surplus revenues of its water system, subject to prior pledges thereof, for such purposes.
However, the authority may fix rates and charges for the service of its streetlight system sufficient to pay all or any part of the cost of operating and maintaining such system.
Va. Code § 15.2-5136