Okla. Stat. tit. 82 § 649
The board of directors shall designate the fiscal year for the district, which fiscal year shall not be changed except with approval of the district court.
Annually, or more often if the court shall order, and within thirty (30) days of the ending of the fiscal year, the board of directors shall make and file with the clerk of the court having jurisdiction of the district, a report of its proceedings and an accounting of the receipts and disbursements for such fiscal year, using forms approved by the State Auditor and Inspector. Any interested person may object to such report, in writing, within sixty (60) days of the ending of the fiscal year. When objections are filed, the Court may order the auditing of district accounts and may order a hearing on such objections, and after giving such notice as the court may direct.
Okla. Stat. tit. 82, § 649