La. Stat. tit. 33 § 3915
Any sewerage district which is operating under Act 26 of 1926, and Acts amendatory thereto, on the effective date of the Revised Statutes shall be governed by the provisions of this Subpart.
A sewerage district created by the governing authority of a municipality prior to July 28, 1926, which has not elected to come under the provisions of Act 26 of 1926, shall continue to operate under the law under which it was created. The board of commissioners of the district may, however, elect by ordinance to come under the provisions of this Subpart. Thereafter the district shall operate under the provisions of this Subpart as though it had originally been established under its provisions, but all taxes voted prior thereto securing the payment of the principal and interest of all outstanding bonds of the district shall continue to be levied until all of the bonds have been retired.
La. R.S. § 33:3915