Wash. Rev. Code § 28A.230.140
The board of directors of every school district shall cause a United States flag being in good condition to be displayed during school hours upon or near every public school plant, except during inclement weather. They shall cause appropriate flag exercises to be held in each classroom at the beginning of the school day, and in every school at the opening of all school assemblies, at which exercises those pupils so desiring shall recite the following salute to the flag: "I pledge allegiance to the flag of the United States of America and to the republic for which it stands, one nation under God, indivisible, with liberty and justice for all". Students not reciting the pledge shall maintain a respectful silence. The salute to the flag or the national anthem shall be rendered immediately preceding interschool events when feasible.
RCW 28A.230.140
Display of national and state flags: RCW 1.20.015.