Black Diamond, WA property records
As of November 2026, Black Diamond, WA has 4,319 parcels on record, with a median assessed value of $646,000 and a median year built of 2012, compiled from King County assessor, treasurer, permit, FEMA, and DNR records aggregated by VetTheHome. As of November 2026, 0 of those 4,319 parcels (0.0%) sit within a FEMA Special Flood Hazard Area, per King County GIS and FEMA flood records aggregated by VetTheHome.
Updated November 2026 · refreshed weekly
Search an address in Black Diamond
Black Diamond by the numbers
Computed 11/9/2026 from county assessor, treasurer, permit, FEMA, and DNR records.
What the public records show
In the 12 months through November 2026, 428 properties in Black Diamond changed hands at a median recorded sale price of $850,945, and 1 building permits were filed, per King County records. As of November 2026, 1,005 parcels in Black Diamond (23%) rely on on-site septic systems rather than municipal sewer, per King County parcel records aggregated by VetTheHome. 0 (0.0%) of parcels in Black Diamond sit in high liquefaction-susceptibility zones mapped by the Washington State DNR. As of November 2026, 42 parcels in Black Diamond carried an unpaid property-tax balance with the King County Treasurer, per records aggregated by VetTheHome. Every figure here is compiled from public records and refreshed weekly; search any Black Diamond address below for parcel-level permit history, tax breakdown, flood and seismic hazards, and septic status.
ZIP codes in Black Diamond
More Washington cities
Explore aggregate King County property data by city — flood, septic, permits, taxes and more.