Okla. Stat. tit. 11, § 11-32-114: Levy and collection of costs - Installments - Issuance

of bonds.

The levy and assessment shall be payable in not more than ten

equal annual installments. Interest on the whole amount remaining

due and unpaid each year shall be at a rate not exceeding eight

percent (8%) per annum. Delinquent installments, and the unpaid

interest thereon, shall draw interest at the rate of twelve percent

(12%) per annum from maturity until paid. Any owner of land within

the improvement district may, within thirty (30) days after the

assessing ordinance is passed, pay the entire amount assessed

against such land. The assessing ordinance may provide that if the

entire amount of all assessments shall not have been paid within

thirty (30) days after passage of the assessing ordinance, special

assessment bonds may be issued, sold, collected and enforced as to

unpaid installments of assessments in the same manner as bonds for

municipal street improvements are issued, sold, collected and

enforced.