Wash. Rev. Code § 79.44.190
When real property subject to an unpaid special assessment for a local improvement levied by any political subdivision of the state authorized to form local improvement or utility local improvement districts is acquired by purchase or condemnation by the state or any political subdivision thereof, including but not limited to any special purpose district, the property so acquired shall continue to be subject to the assessment lien.
An assessment lien or installment thereof, delinquent at the time of such acquisition shall be paid at the time of acquisition, and the amount thereof, including any accrued interest and delinquent penalties, shall be withheld from the purchase price or condemnation award by the public body acquiring the property and shall be paid immediately to the county, city, or town treasurer, whichever is applicable, in payment of and discharge of such delinquent installment lien.
Any installment or installments not delinquent at the time of acquisition shall become due and payable in such year and at such date as said installment would have become due if such property had not been so acquired: PROVIDED, That where such property is acquired by the state of Washington, the balance of the assessment shall be paid in full at the time of acquisition.
For the purpose of this section, the "time of acquisition" shall mean the date of completion of the sale, date of condemnation verdict, date of the order of immediate possession and use pursuant to RCW 8.04.090, or the date of judgment, if not tried to a jury.
RCW 79.44.190