Wash. Rev. Code § 36.26.050
The public defender shall make an annual report to each board of county commissioners within his or her district. If any public defender district embraces more than one county or a cooperating city, the public defender shall maintain records of expenses allocable to each county or city within the district, and shall charge such expenses only against the county or city for which the services were rendered or the costs incurred. The boards of county commissioners of counties and the governing authority of any city participating jointly in a public defender district are authorized to provide for the sharing of the costs of the district by mutual agreement, for any costs which cannot be specifically apportioned to any particular county or city within the district.
Expenditures by the public defender shall be subject to the provisions of chapter 36.40 RCW and other statutes relating to expenditures by counties or cities.
RCW 36.26.050