PDFWAC 332-52-125
Posting.
(1) Can the public post advertisements, signs, or posters on department-managed lands?
(a) Persons shall not erect bills, notices, posters, signs, markers, advertising devices or matter of any kind on department-managed lands without advance written authorization from the department.
(b) A person must contact the region office during business hours to obtain advance written authorization prior to posting advertisements, signs, or posters on department-managed land.
(2) Any violation of this section is an infraction under chapter 7.84 RCW.