Property Taxes

Property taxes are the City’s largest revenue source, making up about 37% of the General Fund. These funds provide the foundation for essential community services, including: 

• Public Safety: 24/7 Police, Fire, and Emergency Medical Services (EMS). 
• Infrastructure: Maintenance of streets, sidewalks, and public buildings. 
• Parks & Recreation: Upkeep of parks and trails, plus programs for youth and seniors. 
• City Operations: Planning and code enforcement, public records, and community communications. 
• Equipment: Replacement of critical vehicles, such as fire engines. 

By funding these core operations, property taxes ensure Mercer Island remains a safe, well-maintained, and vibrant place to live. 

Types of Property Tax 

The City collects two types of property taxes to fund local services: 

1. The Regular Levy 

This is the base funding for general city operations (such as Police, Fire, and Parks). In 2026, this totals $13.6 million. By state law, the City can only increase this amount by 1% annually (or the rate of inflation, whichever is lower), plus an allowance for new construction value determined by the County. 

2. Voter-Approved Levies 

These are additional taxes approved by residents for specific purposes: 

• Levy Lid Lifts: Used for specific operations or projects. Mercer Island currently has one: the Parks Maintenance and Operations Levy, approved in 2022 for 16 years ($1.8 million in 2026). 
• Excess Levies: Used to pay back debt for major capital projects. The City currently has no excess levies. 

Annual Updates 

Every November, the City Council sets the property tax rate for the following year. This process balances the City's budget needs against state limits and other available revenue sources. 

Note on Inflation: The "Implicit Price Deflator" (IPD) used to limit tax increases is a different measure than the "Consumer Price Index" (CPI) used for employee cost-of-living adjustments. 

2026 Levy 

A breakdown of the City's 2026 levy relative to 2025 is provided below: 

_{*The new construction levy, which is not subject to the annual 1.0% limitation, relates to the new and improved properties that have been added to the property tax roll. 
** The refund levy represents the amount that was refunded to property owners who successfully appealed their property valuations by the King County Assessor’s Office.  To make the City whole, the amount of those refunds is re-levied in the following year.} 
  

Assessed Valuation  

For the tax years 2006-2025, the total assessed value of Mercer Island and the percentage change relative to the prior year is summarized below. 

Questions? 

If you have questions about your property taxes, contact the King County Assessor's Office. 

E-mail Address: Assessor.Info@KingCounty.Gov 

Phone: 206-296-7300 
TTY: Relay 711 or 800-833-4388 
Fax: 206-296-0107