King County, WA Historic Preservation: Mills Act Contracts (2026)
California Mills Act property-tax reductions for owners of historic properties who agree to maintenance and rehabilitation standards under a 10-year contract.
Research in progress
We are currently verifying King County's specific local ordinance for mills act contracts. In the meantime,Washington state law generally applies, and below you'll find guidance for finding the official rules and links to related King County ordinances we've already verified.
Washington State Law Context
Washington state law provides the baseline framework for mills act contracts across all municipalities in the state. Individual cities like King County may adopt additional local rules on top of state requirements, which is what makes checking your specific city ordinance important. For King County residents, the safest approach is to follow state law as a baseline and contact City Hall for any additional local requirements.
You can browse all Washington historic preservation to see how cities across the state regulate this topic.
How to find official King County Mills Act Contracts rules
- Search for "King County WA municipal code" to find your city's online code portal (Municode, eCode360, or American Legal Publishing are the most common).
- Look for chapters covering historic preservation, zoning, nuisance, or property maintenance — that's where most mills act contracts rules live.
- Contact King County City Hall's code enforcement, planning, or community development department for clarification.
- Check with your HOA if applicable — many HOAs have stricter rules than the city itself.