Wash. Admin. Code § 162-36 § 162-36-010

Some real estate firms have a practice of sending letters, post cards or printed circulars to residents of a neighborhood where they have a home listed for sale in order to obtain referrals of prospective buyers of the home. Such a practice does not necessarily discriminate against persons on the basis of race, creed, color, national origin, sex, sexual orientation, gender expression or gender identity, marital status, families with children status, the presence of a sensory, mental or physical disability or the use of a trained dog guide or service animal by a disabled person. However, the practice can have a discriminatory effect, and thereby constitute an unfair practice in a real estate transaction within the meaning of this chapter, where:
(1) It is used only in neighborhoods occupied entirely or predominantly by persons of a single race, creed, color, national origin, sex, sexual orientation, gender expression or gender identity, marital status, families with children status, have the presence of a sensory, mental or physical disability, or who use a trained dog guide or service animal as a disabled person, or
(2) Persons of a particular race, creed, color, national origin, sex, sexual orientation, gender expression or gender identity, marital status, families with children status, have the presence of a sensory, mental or physical disability, or use a trained dog guide or service animal as a disabled person living in the same neighborhood are not sent solicitations, or
(3) The content or language of the solicitation invites, promotes or perpetuates residential segregation or discrimination on the basis of race, creed, color, national origin, sex, sexual orientation, gender expression or gender identity, marital status, families with children status, the presence of a sensory, mental or physical disability, or the use of a trained dog guide or service animal by a disabled person.