The department will require any person applying for certification as a water treatment operator, water treatment assistant operator or distribution system operator to take a written, oral and/or practical skills validated examination to determine the applicant's skills, knowledge, ability and judgement. The results of the examination, and the requirements of sections 5-4.3 and/or 5-4.4 of this Subpart, will serve as the basis for approval or disapproval of such application.