Any person affected by a commission final order may petition for rehearing of that order.

(1) Petition. A petition for rehearing must set forth sufficient grounds for rehearing the commission order and must include substantial evidence or an offer of proof in support of the requested relief. Sufficient grounds for rehearing consist of the following:

(a) Changed conditions since the commission entered the order;

(b) Harm to the petitioner resulting from the order that the commission did not consider or anticipate when it entered the order;

(c) An effect of the order that the commission or the petitioner did not contemplate or intend; or

(d) Any good and sufficient cause that the commission did not consider or determine in the order.

(2) Filing and service. The petitioner must file the petition in the docket in which the commission entered the final order and must serve the petition on all parties and persons included in the master service list for that docket.

(3) Responses. Any party in the original proceeding may file a response to the petition within twenty days after the petitioner serves the petition unless the commission establishes a different deadline by notice.

(4) Process. Pursuant to RCW 80.04.200 or 81.04.200, if the petitioner is a public service company and files its petition either no earlier than two years after the effective date of the commission's final order or no earlier than six months after the effective date of a final order that a court has not reviewed and with which the company is in compliance, the commission will conduct a prehearing conference to establish a procedural schedule for commission consideration of the petition. In all other circumstances, the commission will determine whether to accept the petition and, if so, the proceedings the commission will undertake to consider the petition.