Okla. Stat. tit. 82, § 82-1630: Assessment on property within district - Exemptions

Any county in which a drainage district was organized and is

continuing operations pursuant to statutes enacted prior to the

effective date of this section shall be authorized to impose an

assessment upon real or personal property located within the

boundary of the district as such district was organized upon the

effective date of this section for the same purpose, based upon the

assessed value of the property as determined by the current

assessment roll of the county assessor in the county where the

property is located. Properties that are exempt from ad valorem

taxation are exempt from the assessment referred to within this

section.