The order of adoption by which each rule is adopted by an agency shall contain all of the following:
(1) The date the agency adopted the rule;(2) A concise statement of the purpose of the rule;(3) A reference to all rules repealed, amended, or suspended by the rule;(4) A reference to the specific statutory or other authority authorizing adoption of the rule;(5) Any findings required by any provision of law as a precondition to adoption or effectiveness of the rule; and(6) The effective date of the rule if other than that specified in RCW 34.05.380(2).