(1) Evidence, including hearsay, is admissible if, in the judgment of the presiding officer, it is the kind of evidence on which reasonably prudent persons are accustomed to rely in the conduct of their affairs. Findings may be based on such evidence even if it would be inadmissible in a civil trial. In a full hearing, however, the hearing officer shall not base a finding exclusively on such inadmissible evidence unless the hearing officer determines that doing so would not unduly abridge the parties' opportunities to confront witnesses and rebut evidence. The basis for this determination shall appear in the initial order.

(2) The presiding officer will determine the admissibility and relevance of all evidence, including that offered by the parties and/or witnesses, and shall exclude evidence that is excludable on constitutional or statutory grounds or on the basis of evidentiary privilege recognized in the courts of this state. The presiding officer may exclude from consideration evidence that is not relevant. The presiding officer may also exclude from consideration evidence that is immaterial or unduly repetitious.

(3) In general, the presiding officer will not consider statements of personal opinion or statements as to any individual's general reputation or any character trait, unless the presiding officer considers such evidence to be relevant and admissible.

(4) The presiding officer may take official notice of some material that was not offered as evidence by the parties. In full adjudicative proceedings, the process for taking official notice is set forth in RCW 34.05.452.