Okla. Stat. tit. 19, § 19-901.20: Collection of assessments

Upon direction of the board, the clerk must compute and enter in

respective columns of the assessment book the respective sums in

dollars and cents in each fund to be paid on each piece of property

therein enumerated and the clerk shall, no later than twenty (20)

days after the valuations of the county have been certified by the

State Board of Equalization, certify to the county treasurer in

which such district is located the amount of assessment in each fund

levied upon each tract by said board and the said county treasurer

shall enter the amount of each in separate columns of the tax list

of his county and the said assessments shall be collected by the

county treasurer at the same time and in the same manner as all

other taxes are collected in this state. If any such assessment

becomes delinquent, then it shall draw interest as a penalty after

delinquency at the rate of eighteen percent (18%) per annum. All

such assessments and penalties collected or received by the county

treasurer shall be paid by him to the treasurer of the district.

If any assessment shall remain unpaid for six (6) months after

the same is due, the board of directors of the district may

institute an action in the district court to foreclose the lien of

such assessment and penalty and for a reasonable attorney's fees.

All or any portion of the delinquent properties may be joined in one

action. The summons shall be issued upon such petition as in other

civil action and the cause tried by the district court. Judgment

shall be entered for the amount of such unpaid assessment and

penalty, and reasonable attorney fees, which judgment shall bear

interest at the rate of six percent (6%) per annum. In the event

that said judgment together with interest and costs and attorney

fees is not paid within thirty (30) days from its date an order of

sale shall issue by the clerk of said court directing the sheriff of

said county to sell said real estate in manner and form as in case

of the foreclosure of mortgages on real estate, without

appraisement. Such sale shall be subject to existing taxes and

special assessments. In the event that the board of directors of

the district does not institute action to foreclose such delinquent

assessment within one (1) year from the date the same is due, the

holder of any bond or coupon issued under the provisions of this act

may institute an action for and on the behalf of the district to

foreclose the lien of such assessment and penalty. All such actions

to foreclose shall be commenced within three (3) years from the

maturity of the said assessment.