Okla. Stat. tit. 19, § 901.6

The board of directors of the district shall select one (1) of its members for chairman and shall appoint a clerk and a treasurer. The board of directors shall fix the term and duties of the chairman, clerk and treasurer. The chairman and members of the board shall serve without compensation. The treasurer shall give an official bond, in an amount fixed and with sureties approved by the board of directors, conditioned upon the faithful accounting for all money pertaining to the district and coming into his hands.