(a) A district may impose an assessment:
(1) for a district expense;
(2) to finance a project or district service; or
(3) for any other purpose authorized by this chapter.
(b) Money derived from an assessment for one purpose may not be borrowed or otherwise used for a purpose other than the purpose for which the assessment is imposed, except as provided by Subsection (c).

(c) The board shall establish a procedure for the distribution or use of money derived from an assessment that exceeds the amount of money necessary to accomplish the purpose for which the assessment was collected.