(a) Except as provided by Subsection (b) or (c), by Section 1502.059, or by Section 271.052, Local Government Code, a municipality may not use the revenue of a utility system, park, or swimming pool to pay any other debt, expense, or obligation of the municipality until the debt secured by the revenue is finally paid.
(b) This section does not apply to a payment made in lieu of ad valorem taxes previously paid by a private owner of a utility system.
(c) This section does not apply to a payment made from surplus revenue of a utility system, park, or swimming pool, as provided by the proceedings authorizing the issuance of public securities under this chapter.