Real Estate Taxes

Washington State due dates are April 30th and October 31st. Property taxes are collected to support administrations of the state, counties, ports, road districts, rural libraries, cities and towns, schools, natural resource divisions and various other taxing districts.

Your payment must be postmarked by the due date to be considered timely, otherwise interest and/or penalty will apply. 

  • Interest:
    • Delinquencies prior to December 31, 2022, will accrue interest at 1% per month on the FULL amount owing.
    • After January 1, 2023: Delinquencies on all residential real property with four or fewer units, including manufactured/mobile homes, will accrue interest at 0.75% per month on the FULL amount owing. Delinquencies on all other property will accrue interest at 1% per month on the FULL amount owing.
  • Penalty:
    • Delinquencies prior to December 31, 2022, received a penalty of 3% on June 1 and an additional penalty of 8% on December 1 of the delinquent year. Penalty was based on the FULL amount owing at the time of the delinquency.
    • After January 1, 2023, no penalty is assessed on residential real property with four or fewer units, including manufactured/mobile homes. Delinquencies on all other property will receive a penalty of  3% on June 1 and an additional penalty of 8% on December 1 of the delinquent year. Penalty is based on the FULL amount owing at the time of the delinquency.

Tax with a total of $49.99 or less, must be paid in full by April 30.

Checks should be written in blue or black ink and should be made payable to the Cowlitz County Treasurer.

Your canceled check is your receipt. If you want a receipt please send a self addressed stamped envelope. Checks accepted are subject to collection. Non-payment by bank voids receipt. Any non-sufficient check returned from the bank will be charged a $25.00 fee. If the payment coupon is not included please be sure to include the parcel number or account number.

How to pay your taxes:

In Office:

We can accept credit card, check, or cash in office. During closed hours or busy office hours, you can drop off a check payment in the drop box located between the Treasurer’s Office and Assessor’s Office.

By Mail:

Send a check in to
Cowlitz County Treasurer
207 N 4th Avenue
Kelso, WA 98626

By Credit Card:

You can pay by card in our office, online at Autoagent , or call the payment in at 1-844-965-0200.  All credit/ debit cards transactions will incur a fee of 2.4% with a $2.00 minimum. E-Checks incur a flat fee of $2.00.

Did You Know...

The maximum regular tax rate is set by the state legislature. Excess levies or local levies are approved by voters at the polls and include bond issues, maintenance and operation and capital improvements. Voters within a district determine their own tax burden by either approving or disapproving excess levy requests for money.

Washington state is not a Tax Lien state.

Payments under protest must be in writing and included with the timely property tax payment (RCW 84.68.020 and WAC 458-18-215).

Voter-approved taxes are the result of an authorization by the voters during an election process to levy excess taxes for a taxing district to finance Maintenance & Operation expenses and/or to finance debt repayment for the applicable tax year.