Expands the definitions of "vulnerable adult" and "financial exploitation" in chapter 74.34 RCW (abuse of vulnerable adults).

Authorizes the department of social and health services' adult protective services division to enter into agreements with federally recognized tribes to investigate reports of abandonment, abuse, financial exploitation, neglect, or self-neglect of vulnerable adults on property over which a federally recognized tribe has exclusive jurisdiction.

Requires the department of social and health services, when it opens an investigation of a report of abandonment, abuse, financial exploitation, or neglect of a vulnerable adult, to provide a written statement of the rights afforded and other applicable law to alleged victims or legal guardians.