RCW 30A.22.140

Payments of funds on deposit in a single account may be made by a financial institution to or for the depositor regardless of whether the depositor is, in fact, the actual owner of the funds. Payments of funds on deposit in an account having two or more depositors may be made by a financial institution to or for any one or more of the depositors named on the account without regard to the actual ownership of the funds by or between the depositors, and without regard to whether any other depositor or depositors so named are deceased or incompetent at the time the payments are made.