Black Diamond Property Tax Quick Facts
- Location
- Black Diamond, Washington
- King County
- Assessed By
- King County Assessor
- Appeal Deadline
- July 1
- County Tax Rate
- ~1.03%
- Shared with Black Diamond
How to Appeal Property Taxes in Black Diamond
Check your assessment
Enter your Black Diamond address for a free 60-second check. We compare your assessed value against comparable sales and neighborhood data.
Get your evidence packet
If over-assessed, pay $45 for a complete appeal packet with comparable sales, equity analysis, and pre-filled forms for King County.
File your appeal
Submit your appeal to King County Assessor before July 1. Our filing guide walks you through every step.
About the Black Diamond Property Market
Black Diamond is a city located in King County, Washington. Every property inside the Black Diamond city limits is assessed by King County Assessor, which applies Washington property tax rules uniformly across the county.
Because Black Diamond property values are set at the county level, the $650,000 county median home value and 1.03% effective tax rate apply to homes throughout the city. Homeowners who believe their Black Diamond home is over-assessed have the right to file a appeal directly with King County Assessor before the July 1 deadline.
Washington allows the assessor to defend or adjust the assessed value during a appeal, so Black Diamond homeowners should build a strong evidence-based case before filing — which is exactly what ProtestMax generates for $45.
Black Diamond Property Market Context
The property tax picture in Black Diamond is shaped as much by Washington statewide policy as by anything unique to a city.
Washington market character
Washington has no state income tax, and property taxes carry significant weight at around 0.9% effective. The state reassesses annually in most counties, and Seattle-metro markets have produced aggressive assessed-value jumps.
How Washington handles appeals
Washington homeowners appeal to the county Board of Equalization, then the state Board of Tax Appeals. The state is protest-friendly and evidence-driven, and BOE petitions are accessible to self-filers.
When to file in Black Diamond
Petitions must be filed by July 1 or within 60 days of notice mailing, whichever is later. Notices typically mail in May or June.
Common Black Diamond Property Types
Black Diamond homeowners typically file protests across these property categories:
Single-family homes
The most common residential type and the dominant protest category.
Condominiums
Common in denser parts of the city and near employment centers.
Townhouses
Attached-home neighborhoods in newer subdivisions.
Small multi-family
Duplexes and 2-4 unit buildings assessed as income property.
Commercial
Retail, office, and small commercial along major corridors.
ProtestMax supports all of the above property types in Black Diamond. Each appealpacket is tailored to the property's classification and uses comparable sales from Black Diamond and surrounding King County neighborhoods.