Wash. Rev. Code § 44.04.100
Any person desiring to contest the election of any member of the legislature, may, at any time after the presumptive election of such member and before the convening of the ensuing regular session of the legislature, have the testimony of witnesses, to be used in support of such contest, taken and perpetuated, by serving not less than three days' written notice upon the member whose election he or she desires to contest, of his or her intention to institute such contest and that he or she desires to take the testimony of certain witnesses named in such notice, at a time and place named therein, before a notary public duly commissioned and qualified and residing in the county where the presumptive member resides, giving the name of such notary public, which deposition shall be taken in the manner provided by law for the taking of depositions in civil actions in the superior court. The presumptive member of the legislature, whose election is to be contested, shall have the right to appear, in person or by counsel, at the time and place named in the notice, and cross examine any witness produced and have such cross examination made a part of such deposition, and to produce witnesses and have their depositions taken for the purpose of sustaining his or her election. The notary public before whom such deposition is taken shall transmit such depositions to the presiding officer of the senate, or house of representatives, as the case may be, in which said contest is to be instituted, in the care of the secretary of state, at the state capitol, by registered mail, and it shall be the duty of the secretary of state upon the convening of the legislature to transmit said depositions, unopened, to the presiding officer of the senate, or the house of representatives, as the case may be, to whom it is addressed, and in case such contest is instituted said depositions may be opened and read in evidence in the manner provided by law for the opening and introduction of depositions in civil actions in the superior court.
RCW 44.04.100
Contest of elections: Chapter 29A.68 RCW.
Depositions: Rules of court: CR 26 through 37.
Legislature to judge election and qualifications of members: State Constitution Art. 2 s 8.
Recall: State Constitution Art. 1 ss 33, 34, chapter 29A.56 RCW.