Wash. Rev. Code § 81.04.120
At the time fixed for the hearing mentioned in RCW 81.04.110, the complainant and the person or corporation complained of shall be entitled to be heard and introduce such evidence as he or she or it may desire. The commission shall issue process to enforce the attendance of all necessary witnesses. At the conclusion of such hearing, the commission shall make and render findings concerning the subject matter and facts inquired into and enter its order based thereon. A copy of such order, certified under the seal of the commission, shall be served upon the person or corporation complained of, or his or her or its attorney, which order shall, of its own force, take effect and become operative twenty days after the service thereof, except as otherwise provided. Where an order cannot, in the judgment of the commission, be complied with within twenty days, the commission may prescribe such additional time as in its judgment is reasonably necessary to comply with the order, and may, on application and for good cause shown, extend the time for compliance fixed in its order. A full and complete record of all proceedings had before the commission, or any member thereof, on any formal hearing had, and all testimony shall be taken down by a stenographer appointed by the commission, and the parties shall be entitled to be heard in person or by attorney. In case of an action to review any order of the commission, a transcript of such testimony, together with all exhibits introduced, and of the record and proceedings in the cause, shall constitute the record of the commission.
RCW 81.04.120