The charges for services as provided in RCW
43.20B.425 shall be based on the rates established for the purpose of receiving federal reimbursement for the same services. For those services for which there is no applicable federal reimbursement-related rate, charges shall be based on the average per capita costs, adjusted for inflation, of operating each of the residential habilitation centers for the previous reporting year taking into consideration all expenses of institutional operation, maintenance and repair, salaries and wages, equipment and supplies: PROVIDED, That all expenses directly related to the cost of education for persons under the age of twenty-two years shall be excluded from the computation of the average per capita cost. The department shall establish rates on a per capita basis and promulgate those rates or the methodology used in computing costs and establishing rates as rules of the department in accordance with chapter
34.05 RCW. The department shall be charged with the duty of collection of charges incurred under RCW
43.20B.410 through
43.20B.455, which may be enforced by civil action instituted by the attorney general within or without the state.