Seattle Municipal Code § 7.24.030

A landlord may screen a potential tenant and additional residents other than the tenant's
immediate family to determine whether a potential tenant can become party to a rental
agreement or additional residents can occupy the rental unit. A landlord may obtain
a screening report under subsection 14.08.040.F and Chapter 14.09 for members of a tenant's immediate family but may not exclude any member of the
tenant's immediate family from occupancy or becoming a party to the rental agreement
based on information in the screening report, except as provided in Section 7.24.032. A landlord must comply with all other screening requirements required by law.

6.

Parties to the rental agreement

A landlord may require by written notice that any resident who is not a member of
the tenant's immediate family become a party to the rental agreement. If that resident
fails to become party to the rental agreement within 30 days after receiving a written
notice from the landlord requiring that resident to become a party, that resident
shall vacate the unit within 45 days after receiving that notice.

J.

Right of first refusal

1.