Washington Revised Code Title 84. Property Taxes § 84.69.140. Interest shall be allowed on amount recovered

In any action in which recovery of taxes is allowed by the court, the plaintiff is entitled to interest on the taxes for which recovery is allowed at the rate specified in RCW 84.69.100 from the date of collection of the tax to the date of entry of judgment, and such accrued interest shall be included in the judgment.