(a) The advisory body shall prepare an ongoing service plan and present the plan to the governing body of the municipality or county for review and approval. The governing body may approve the plan only by ordinance or order. The governing body may assign responsibility for the plan to another entity in the absence of an advisory body.
(b) The service plan must:
(1) cover a period of at least five years;
(2) define the annual indebtedness and the projected costs for improvements; and
(3) include a copy of the notice form required by § 5.014, Property Code.

(c) Not later than the seventh day after the date the governing body of a municipality or county approves a service plan, the municipality or county shall file a copy of the plan with the county clerk of each county in which all or part of the public improvement district is located.
(d) The governing body of the municipality or county shall review and update the service plan annually for the purpose of determining the annual budget for improvements. Except for the service plan for a district described by § 372.0035, the governing body may amend or update the plan only by ordinance or order.
(e) Not later than the seventh day after the date the governing body of a municipality or county amends or updates the service plan, including the notice form required by § 5.014, Property Code, the municipality or county shall file a copy of the amended or updated plan with the county clerk of each county in which all or part of the public improvement district is located.