Okla. Stat. tit. 19, § 19-339.8: Debt collection services

A. The board of county commissioners may enter into a contract

with a collection agency for the provision of collection services

for debts and accounts receivable including, but not limited to,

unpaid fees, penalties, interest, and other sums due the county, as

applicable.

B. The board of county commissioners that enters into a

contract with a collection agency pursuant to this section may

authorize the addition of a collection fee in an amount not to

exceed thirty-five percent (35%) on each item described in

subsection A of this section that has been referred by the county to

the collection agency for collection.