If the mobile home is going to be moved, as a condition of sale, obtain a tax certificate (moving permit) from the Assessor's Office. There is no charge for the tax certificate. Take the tax certificate to the Treasurer's Office to be certified that any property taxes due on the mobile home have been paid, and receive an orange decal which must be displayed on the mobile home while it is being moved. It is a violation of Washington state law to move a mobile home without a validated tax certificate and orange decal. When all property taxes have been paid, the Treasurer's Office will issue a tax verification form (half sheet). The tax verification form, and the current mobile home title, can be taken to the Licensing Department in the Auditor's Office to pay sales tax and transfer the title into the new owner's name.
If the mobile home is not going to be moved, go to the Treasurer's Office to complete a Mobile Home Excise Tax Affidavit and pay any excise tax that may be due. This affidavit must be signed by the buyer and the seller, and is required along with the current title, to transfer title in the Licensing Department of the Auditor's Office. Please be careful that you don't reduce the print and/or form size when printing these documents from the Department of Revenue website.
Follow the link below, then look for Real estate excise tax mobile home affidavit. REET Mobile Home Affidavit (PDF)