Wash. Rev. Code § 64.60.030
Any person who records, or enters into, an agreement imposing a private transfer fee obligation in the person's favor after April 13, 2011, is liable for (1) any damages resulting from the imposition of the private transfer fee obligation on the transfer of an interest in the real property including, but not limited to, the amount of any private transfer fee paid by a party to the transfer, and (2) reasonable attorneys' fees, expenses, and costs incurred by a party to the transfer or mortgagee of the real property to recover any private transfer fee paid or in connection with an action to quiet title. If an agent acts on behalf of a principal to record or secure a private transfer fee obligation, liability must be assessed to the principal, rather than the agent.
RCW 64.60.030