Wash. Rev. Code § 41.44.250
The payment of any retirement allowance to a member who has been retired from service shall be suspended during the time that the beneficiary is in receipt of compensation for service to any city or town that is a member of the statewide city employees' retirement system, except as to the amount by which such retirement allowance may exceed such compensation for the same period. It is the intent of this section to prevent any retired person from being able to receive both his or her retirement allowance and compensation for service to any city or town that is a member of the statewide city employees' retirement system: PROVIDED, That nothing in this section shall prevent county or state welfare departments from furnishing to any retired employee under the terms of this chapter the hospital, medical, dental, and other benefits granted to pensioners under the provisions of Title 74 RCW.
RCW 41.44.250