John A. Rosenau, Franklin County Assessor

John A. Rosenau
Franklin County Assessor

John A. Rosenau
County Assessor


Piper Mitchell
Chief Deputy Assessor


Nikki Morgan
Chief Appraiser

Assessor's Office Phone Number: (509) 545-3506
Assessor Email:
Personal Property Email:
Mapping and platting:

Welcome to the Franklin County Assessor's Office


Our goal in the Franklin County Assessor's Office is to provide you with exceptional service in a caring, courteous and respectful manner. The assessor's website is designed with the goal in mind to serve your needs and answer as many of your questions as we can anticipate.


The Assessor's Office does not establish the dollar amount of taxes required nor do we bill or collect taxes. Taxpayers, state limitations and each district's assessed value determines the tax rate for each district. The county Treasurer bills and collects the required tax.


It is the responsibility of the Assessor's Office to ensure that all property owners are treated fairly and impartially in accordance with our state laws. It is the goal of the Assessor's Office to provide superior service to our community and residents to continually demonstrate fairness, honesty and integrity in everything we do.


Diagram: Market Sales used in Mass Appraisal Process determine Appraised Value as of January 1, 2020, Used to calculate Taxes Payable in 2021

The Franklin County Assessor's Office is mailing Real Property Change of Value Notices late August, 2021.

During this challenging time, there may be questions regarding how the COVID event may impact the assessed value of your property. RCW 84.40.020 requires property to be valued as of January 1st for taxes payable the following year. The notice being mailed is for the property value as of January 1, 2020 and is based upon 2019 market data, which is prior to COVID. The value notice you receive next year, in the summer of 2021, will be based upon the 2020 market data which may or may not indicate an impact from the 2020 economic conditions. If you want more information, please visit the Assessor's website at or contact the Franklin County Assessor's Office at 509-545-3506 or by email at