Wash. Rev. Code § 86.09.502
The owner or person in possession of any real estate offered for sale for assessments due thereon may designate in writing to the county treasurer, by whom the sale is to be made, and prior to the sale, what portion of the property he or she wishes sold, if less than the whole; but if the owner or possessor does not, then the treasurer may designate it, and the person who will take the least quantity of the land, or in case an undivided interest is assessed, then the smallest portion of the interest, and pay the assessment and costs due, including one dollar to the treasurer for duplicate of the certificate of sale, is the purchaser. The treasurer shall account to the district for said one dollar. If the purchaser does not pay the assessment and costs before ten o'clock a.m. the following day, the property must be resold on the next sale day for the assessments and costs. In case there is no purchaser in good faith for the same on the first day that the property is offered for sale, and if there is no purchaser in good faith when the property is offered thereafter for sale, the whole amount of the property assessed shall be struck off to the district as the purchaser, and the duplicate certificate shall be delivered to the secretary of the district, and filed by him or her in the office of the district. No charge shall be made for the duplicate certificate where the district is the purchaser, and in such case the treasurer shall make an entry, "Sold to the district", and he or she will be credited with the amount thereof in settlement. The district, as a purchaser at said sale, shall be entitled to the same rights as a private purchaser, and may assign or transfer the certificate of sale upon the payment of the amount which would be due if redemption were being made by the owner. If no redemption is made of land for which the district holds a certificate of purchase, the district will be entitled to receive the treasurer's deed therefor in the same manner as a private person would be entitled thereto.
After receiving the amount of assessments and costs, the county treasurer must make out in duplicate a certificate, dated on the day of sale, stating (when known) the names of the persons assessed, a description of the land sold, the amount paid therefor, that it was sold for assessments, giving the amount and the year of assessment, and specifying the time when the purchaser will be entitled to a deed. The certificate must be signed by the treasurer making the sale and one copy delivered to the purchaser, and the other filed in the office of the county treasurer of the county in which the land is situated: PROVIDED, That upon the sale of any lot, parcel, or tract of land not larger than an acre, the fee for a duplicate certificate shall be twenty-five cents and in case of a sale to a person or a district, of more than one parcel or tract of land, the several parcels or tracts may be included in one certificate.
RCW 86.09.502