Okla. Stat. tit. 19 § 863.40
All plumbing materials, equipment and methods of installation thereof in every county subject to the provisions of this act shall be in strict conformity with approved standards for health and safety to persons and property. Compliance with the plumbing code as said code exists at the date of passage of this act of any city having a population of from one hundred and eighty thousand (180,000) to two hundred and forty thousand (240,000) according to the last Federal Decennial Census located in any county as defined herein shall be deemed to be prima facie evidence of compliance with this act.
The board of county commissioners of any county within the provisions of this act are hereby authorized to create, by resolution duly adopted, the office of plumbing inspector for such county. Such inspector shall be a person who holds a certificate of master plumber under the provisions of the laws of this state, relating to cities of two thousand (2,000) or more inhabitants, and shall have had at least ten (10) years practical experience as a master plumber. Such plumbing inspector is authorized to inspect all plumbing installations in any county within the provisions of this act, to determine that the same are done within the provisions of this act. However, where any such plumbing installations are subject to inspection by the duly qualified, appointed and acting plumbing inspector of any city or town, having a system of water supply or sewerage by reason of contract with the owner or builder of such plumbing facilities or otherwise, approval by such municipal plumbing inspector shall be deemed to establish compliance with this act and inspection by the county plumbing inspector or county plumbing permits will be unnecessary.
The board of county commissioners may, on recommendation of the county plumbing inspector, adopt all necessary rules and regulations to carry out purposes of this act and may prescribe the necessary permits, notices and inspection procedure and set and determine the fees therefor. Such fees shall be reasonable and shall be sufficient to meet the expenses of operation of the office of county plumbing inspector. The county commissioner shall be authorized to hire such deputy plumbing inspectors for such terms and at such compensation as they may deem reasonable. The county plumbing inspector shall issue, without examination, certificates of competency to all persons holding such a certificate issued by any city or town in the State of Oklahoma of two thousand (2,000) or more inhabitants, provided that such certificate has been issued or renewed for the year in which application therefor to the county plumbing inspector is made.
Okla. Stat. tit. 19, § 863.40