(1) Notice of a hearing will be mailed to all parties and to all persons having submitted written petitions to intervene not less than twenty calendar days before the hearing date unless a different period is required by law. The notice shall include the information specified in RCW 34.05.434 and if the hearing is to be conducted by teleconference call the notice shall so state.

(2) The notice shall state that if a limited-English speaking or hearing-impaired party or witness needs an interpreter, a qualified interpreter will be appointed and that there will be no cost to the party or witness. The notice shall also state that persons with disabilities may request reasonable accommodations to allow their participation in the hearing. The notice shall include a form for a party to indicate if an interpreter is needed and identification of the primary language, or if a participant is hearing impaired; or to describe the reasonable accommodations requested.

(3) Defects in notice may be waived if the waiver is knowing and voluntary.