Okla. Stat. tit. 82 § 635
When the assessment roll is placed on file in the office of the district, notice by publication shall be given to property owners that they may pay their assessments. Any owner of real property assessed for the execution of the official plan under the provision of this act shall have the privilege of paying such assessment to the treasurer of the board of directors within thirty (30) days from the time such assessment is placed on file in the office of the district, and the amount to be paid shall be the full amount of the assessment less any amount added thereto to meet interest. When such assessment has been paid, the secretary of the board shall enter upon the said assessment record opposite each tract for which payment is made the words "paid in full" and such assessment shall be deemed satisfied. The payment of such assessment shall not relieve the land owners from the necessity for the payment of a maintenance assessment nor for the payment of any further assessment which may be necessary as herein provided. Any property owner failing to pay assessments in full as provided for herein shall be deemed to have consented to the issuance of bonds as provided for in this act, and to payment of interest thereon.
After the expiration of the period of thirty (30) days within which the property owners may pay their respective assessments, as limited herein, the treasurer of the district shall certify to the board of directors the aggregate of the amount so paid, and thereupon the board of directors shall pass and spread upon their records a bonding resolution in which shall be stated the amount of the assessment, and the amount thereof paid as aforesaid, and thereupon the board shall in the same resolution apportion the uncollected assessment into installments or levies, provide for the collection of interest upon the unpaid installments, and they may order the issuance of bonds (in an amount not exceeding ninety percent (90%) of the levy) in anticipation of the collection of said installments. The residue of the special assessment so levied (not less than ten percent (10%) shall constitute a contingent account to protect the bonds from casual default, and any part thereof in excess of the ten percent (10%) of the next installment of maturing bond principal, together with the next two installments of semiannual interest, if not needed for this purpose, may be transferred from time to time to the maintenance fund of the district.
Okla. Stat. tit. 82, § 635