Buildings and property

Homeowner and renter resources

On-site sewage (septic) systems

Plumbing and gas piping

Green and sustainable building

Resources for developers, builders, architects, and homeowners interested to build toward a sustainable King County.

Historic preservation

Learn about the Historic Preservation Program and its efforts to preserve the history of King County.

Property research and maps

Learn more about landslide mapping and property specific development conditions, or access reference maps for planning support.

Property tax assessments

Learn more about how we assess and tax residential property.

Property tax payments

After King County issues a building permit, inspections are required at different stages of the project.