Certificates shall be issued without examination under the following conditions:
(1) Certificates shall be issued without application fee to operators who, on January 1, 1978, hold certificates of competency attained under the voluntary certification program sponsored jointly by the state department of social and health services, health services division, and the Pacific Northwest section of the American water works association.
(2) Certification shall be issued to persons certified by a governing body or owner of a public water system to have been the operators of a purification plant or distribution system on January 1, 1978, but only to those who are required to be certified under RCW
70A.120.030(1). A certificate so issued shall be valid for operating any plant or system of the same classification and same type of water source.
(3) A nonrenewable certificate, temporary in nature, may be issued to an operator for a period not to exceed twelve months to fill a vacated position required to have a certified operator. Only one such certificate may be issued subsequent to each instance of vacation of any such position.