Washington Revised Code Title 39. Public Contracts and Indebtedness § 39.44.120. Payment of coupon interest

If so provided in the proceedings authorizing the issuance of any such bonds, upon the registration thereof as to principal, or at any time thereafter, the coupons thereto attached, evidencing all interest to be paid thereon to the date of maturity, may be surrendered to the officer or agent hereinafter provided and the bonds shall also become registered as to interest. Such coupons shall be canceled by such officer or agent, who shall sign a statement endorsed upon such bond of the cancellation of all unmatured coupons and the registration of such bond. Thereafter the interest evidenced by such canceled coupons shall be paid at the times provided therein to the registered owner of such bond in lawful money of the United States of America mailed to his or her address.