Interest Due for Late Payments

Under Washington State law (RCW 39.76.010), if a public agency fails to make payment to a contractor, consultant, or vendor in a timely manner, the agency must pay interest at the rate of one percent (1%) per month on the amounts due.

The law considers a payment to be timely if it is made on the date specified in the contract, or if no date is specified, within 30 days of receipt of a properly completed invoice, or upon receipt of the goods or services, whichever is later.