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Leadership team

Meet King County Assessor John Wilson and his team.

King County Assessor John Wilson

John Wilson, King County Assessor

John is serving his second term after winning reelection in 2019. He's earned praise as one of King County's most innovative leaders.

Among John's accomplishments as Assessor:

  • He led the office in introducing the Taxpayer Transparency Tool. It lets you see how ballot measures will impact your property taxes. 
  • He worked with community organizations to help pass property tax relief for senior citizens. Thousands of new applicants can stay in their homes as a result.
  • He helped pass laws making it easier to fix errors and reimburse taxpayers for overpayments.
  • He's a leader in identifying surplus public and vacant private property. Both provide innovative short and long-term housing solutions for homeless residents.

John served as Chief Deputy Assessor for four years. He gained a reputation for developing technology that enhances customer service and reduces costs. He also rebuilt the Assessor's website, which led to a tenfold increase in monthly pageviews.

As a member of King County's Information Technology staff, John led an effort to build a culture of innovation among county employees and departments.

John's earlier career included handling communications for the late former Congressman Al Swift. He also served as communications director and chief of staff to former King County Executive Ron Sims. Under Sims, John helped drive projects on freight mobility and the expansion of parks and open space.

John is also an experienced public affairs consultant. He worked with the American Civil Liberties Union to reform Washington's marijuana laws. He also worked with the state and Whatcom County to identify economic opportunities during the 2010 Winter Olympic Games in Vancouver, B.C.

A former journalist for KING 5 News, John is the recipient of the DuPont Columbia Award. His work appeared on KING, ABC, NBC, and CNN. He also used to report for The Seattle Times and Seattle Weekly.

John is the father of four adult children. He enjoys reading, cooking, jazz, hiking, and traveling.

Al Dams, Chief Deputy Assessor

Al is a respected public servant with almost 30 years of experience for King County. He's held leadership roles in Assessments, Parks, Executive Services, and Public Works. 

Jeff Darrow, Residential Division Director

Jeff has been with the Assessor’s office for two decades. He has more than 25 years of experience as a real estate appraiser and holds a Bachelor of Arts in marketing from Western Washington University.

Jeff directs the Residential Division, which is responsible for inspecting and valuing all residential parcels in King County.


Jim Hall CAE, RES, MAS, Chief Appraiser and Appeals Division Manager

Jim was hired as the Chief Appraiser in April of 2020. He is an appraiser and valuation modeler with more than 32 years of experience in many types of real and personal property. He holds a Diploma in Urban Land Economics and a Certificate in Real Property Assessment from the University of British Columbia. He's a Certified General Appraiser in the state of Washington and is an Accredited Appraiser by the Washington State Department of Revenue. He is also a senior instructor for the International Association of Assessing Officers. Before joining King County, Jim was the manager of the Commercial, Industrial and Appeals section(s) of the Pierce County Assessor Treasurer’s Office and represented Pierce County in complex valuation disputes for 24 years.

Jim supervises the Appeals Division, providing oversight of appeals and assessment litigation.

Hoang Nguyen, Information Services Division Director

Hoang has been with the Assessor's office for 16 years. Hoang has a Bachelor of Science in computer engineering. Hoang has won awards from the National Association of Counties and the International Association of Assessing Officers.

Hoang directs the Information Services Division, which supports the web portal, smartphone apps, and the Computer-Assisted Mass Appraisal (CAMA) system.

Ruth Peterson, Commercial Division Director

Ruth has enjoyed being a part of the Assessor’s office for 30 years. Her credentials include a Bachelor of Arts degree in Business Administration and she’s also a certified general appraiser. Working with disabled adults, underrepresented communities, and serving the public are some of her many interests.

Ruth oversees the Business Commercial Division which values commercial parcels, personal property, residential condominiums, multi-family structures, and floating homes.

Mindy Tiangson, Accounting Division Director

Mindy has more than 30 years of experience with the Assessor's office. She's contributed work for residential and commercial appraisals and public information. She holds a certified real estate appraiser's license.

Mindy directs the Accounting Division, which processes about 700,000 property valuations each year. They also review and approve senior, disability, and current-use exemptions.

Rich Watson, Administrative Services Division Director

Rich has served King County in human resource leadership roles for more than 24 years. He holds a Bachelor of Science in applied mathematics from the University of New Mexico and a Master of Business Administration from Oregon State University. He's also a certified mediator. Rich served 17 years in the United States Navy, as a submarine officer prior to joining King County.

Rich manages the Administrative Services Division, which oversees human resources, budgets, finance and procurement.