Generally, an employer cannot discriminate in any way in compensation based on gender between employees performing similar jobs.[1] Employers are also prohibited from depriving an employee of career advancement opportunities on the basis of gender.
a. Affirmative Defenses: To justify a pay disparity, an employer can assert that it was based in good faith on a bona fide job-related factor or factors that: (i) are consistent with business necessity; (ii) are not based on or derived from a gender-based differential; and (iii) account for the entire differential. Such bona fide factors include, but are not limited to: (A) education, training, or experience; (B) a seniority system; (C) a merit system; (D) a system that measures earnings by quantity or quality of production; (E) a bona fide regional difference in compensation levels.[2]
b. Retaliation: An employer may not retaliate, discharge, or otherwise discriminate against an employee because the employee has filed any complaint, or instituted or caused to be instituted any proceeding under Washington’s equal pay law or against an employee testifying in such a proceeding.[3]
[1] RCW 49.58.005, .020, .030.
[2] RCW 49.58.020(3)(a) and (b).
[3] RCW 49.58.050.