Wash. Rev. Code § 48.43.435
(1)
(a) Except as provided in (b) of this subsection, when calculating an enrollee's contribution to any applicable cost-sharing or out-of-pocket maximum, a health carrier offering a nongrandfathered health plan with a pharmacy benefit, or a health care benefit manager administering benefits for the health carrier, shall include any cost-sharing amounts paid by the enrollee directly or on behalf of the enrollee by another person for a covered prescription drug that is:
(ii) With a generic equivalent or a therapeutic equivalent preferred under the health plan's formulary where the enrollee has obtained access to the drug through:
(6) For purposes of this section:
[ 2022 c 228 s 1.]