In the Administrative Procedure Act, you can find RCW 34.05.325
Public participation—Concise explanatory statement. Within that section there is this statement;

(4) The agency head, a member of the agency head, or a presiding officer designated by the agency head shall preside at the rule-making hearing. Rule-making hearings shall be open to the public. The agency shall cause a record to be made of the hearing by stenographic, mechanical, or electronic means. Regardless of whether the agency head has delegated rule-making authority, the presiding official shall prepare a memorandum for consideration by the agency head, summarizing the contents of the presentations made at the rule-making hearing, unless the agency head presided or was present at substantially all of the hearings. The summarizing memorandum is a public document and shall be made available to any person in accordance with chapter 42.56 RCW.