(1) The local board of health shall ensure that individuals who conduct inspections of on-site wastewater treatment systems as defined in RCW 18.210.010 or who otherwise conduct reviews of such systems are qualified in the technology and application of on-site sewage treatment principles. A certificate of competency issued by the state board of registration for professional engineers and land surveyors is adequate demonstration that an individual is competent in the engineering aspects of on-site wastewater treatment system technology.
(2) A local board of health may allow noncertified individuals to review designs of, and conduct inspections of, on-site wastewater treatment systems, as defined in RCW 18.210.010, pursuant to this section under the supervision of a certified individual. Such supervised practice may continue for a maximum of four years after the date of hire.