Wash. Rev. Code § 19.16.240
Each licensee, other than an out-of-state collection agency, shall at all times maintain a separate bank account in this state in which all moneys collected by the licensee shall be deposited except that negotiable instruments received may be forwarded directly to a customer. Moneys received must be deposited within ten days after posting to the book of accounts. In no event shall moneys received be disposed of in any manner other than to deposit such moneys in said account or as provided in this section.
The bank account shall bear some title sufficient to distinguish it from the licensee's personal or general checking account, such as "Customer's Trust Fund Account". There shall be sufficient funds in said trust account at all times to pay all moneys due or owing to all customers and no disbursements shall be made from such account except to customers or to remit moneys collected from debtors on assigned claims and due licensee's attorney or to refund over payments except that a licensee may periodically withdraw therefrom such moneys as may accrue to licensee.
Any money in such trust account belonging to a licensee may be withdrawn for the purpose of transferring the same into the possession of licensee or into a personal or general account of licensee.
RCW 19.16.240