Mississippi Administrative Code
Title 15 - Mississippi Department of Health
Part 20 - Bureau of Public Water Supply
Subpart 72 - Public Water Supply
Chapter 2 - REGULATION GOVERNING THE CERTIFICATION OF MUNICIPAL AND DOMESTIC WATER SYSTEM OPERATORS
Subchapter 4 - General Qualifications for all Certified Waterworks Operators
Rule 15-20-72-2.4.3

An operator whose certification has been expired for twenty-four (24) months or less shall be eligible to receive a new waterworks operator certification at a level no higher than the certification previously issued by the Bureau if he/she successfully passes the written examination required by the Bureau expired more than twenty-four (24) months must successfully pass the written examination required by the Bureau and comply fully with the provisions of Rule 2.4.1.

Miss. Code Ann. § 21-27-205