Property Taxes in Black Diamond, Washington
Median Black Diamond, Washington effective property tax rate: 0.88%, significantly lower than the national median of 1.02%, and lower than the Washington state median of 0.92%.
Median Black Diamond, Washington home value: $706,000
Median annual Black Diamond, Washington tax bill: $6,169, $3,769 higher than the national median property tax bill of $2,400.
How are property taxes in King County calculated?
Property taxes in Black Diamond, Washington are calculated based on the tax assessed value, which is often lower than the actual market value due to property tax exemptions such as the homestead or senior exemption.
Understanding Black Diamond's property tax system, exemptions, and reduction opportunities can lead to significant savings. Regardless of where you live in Black Diamond, knowing local tax details benefits homeowners and investors.
Last Updated April 13, 2026
How Does the Black Diamond Property Tax Calculator Work?
Use this Black Diamond property tax calculator to estimate your annual tax bill. Enter your property's assessed value and our calculator applies Black Diamond's median effective tax rate of 0.88% — based on actual property records in King County — to generate your estimate.
Enter your property's estimated assessed value — the figure the local appraisal district uses to calculate your bill, which reflects any exemptions you hold and is typically lower than your home's market value. Our calculator applies Black Diamond's median effective rate across all local levies, providing a more accurate estimate than applying a single county millage rate.
Your bill may vary by ZIP code within Black Diamond: rates range from 0.88% in 98010 to 0.88% in 98010, primarily due to differences in school district levies and local assessment districts.
If your estimate is higher than expected, Ownwell can appeal your Black Diamond assessment — you only pay if we save you money.
About Black Diamond Property Taxes
About Property Taxes in Black Diamond, King, Washington
Black Diamond’s median effective property tax rate of 0.88% is lower than the Washington state median of 0.92% and lower than the national median of 1.02%. This rate reflects the King County base levy combined with local school district levies and local improvement districts that can vary by subdivision throughout the city.
Property tax rates are not uniform across Black Diamond. Homeowners in ZIP code 98010 carry a median effective rate of 0.88%, and the same ZIP also reflects the city’s median home price of $706,000 and median property tax bill of $6,169. Understanding how assessed value and local taxing districts affect your bill can make a meaningful difference to your annual property taxes.
Black Diamond homeowners who believe their assessed value is too high can file a formal appeal with the Tax Assessor after the notice date in July each year.
If your estimated bill seems higher than expected, Ownwell can review your assessment and protest on your behalf. You only pay if we save you money.
Property Tax Rates Across Black Diamond, King County, Washington
As noted earlier, local government entities set tax rates, which can vary widely within a state.
Why? Because annually, each county estimates its required budget to provide services and divides that by the total value of all taxable property within its jurisdiction. This calculation results in the property tax rate.
While there are votes and laws involved in setting tax rates and budgets, in a nutshell, this is the annual process.
Below, you can compare Black Diamond's effective property tax rate to other cities in Washington and the median property tax rates in Washington and the U.S.
Our median effective property tax rate (tax bill ÷ assessor's market value) accounts for exemptions and deductions, making it more accurate than the general median tax rate, which is the midpoint of statutory rates before adjustments.
Median Effective Black Diamond Tax Rate
0.88%
Our median effective property tax rate (tax bill ÷ assessor's market value) accounts for exemptions and deductions, making it more accurate than the general median tax rate, which is the midpoint of statutory rates before adjustments.
Median Effective King County Tax Rate
0.99%
Median Effective Washington Tax Rate
0.92%
Median Effective United States Tax Rate
1.27%
Property Tax Rates Across Black Diamond, King County, Washington
| Zip | 10th Percentile | 25th Percentile | Median Tax Rate | 75th Percentile | 90th Percentile |
|---|---|---|---|---|---|
| 98010 | 0.86% | 0.87% | 0.88% | 0.92% | 1.04% |
Source: Ownwell
Save on Your Property Taxes and More With Ownwell
$774
Average Annual Tax Savings
Property Tax Assessment Values Across Black Diamond, King County, Washington
When examining property taxes in Black Diamond, Washington, understanding the distinction between "market value" and "assessed value" is crucial.
The market value is what a willing buyer would pay to a willing seller in an open and competitive market, often influenced by location, property condition, and economic market trends. The King County assessment process estimates the market value for tax purposes.
The assessed value is the market value minus any applicable exemptions or limits determined by local laws and offerings. The tax assessed value is the figure used to calculate your property taxes or the amount multiplied by your tax rate to get your tax bill.
Assessment notices:
In King County, assessment notices are sent in the spring each year. They'll typically reach your mailbox by the middle of July.
Each property owner receives an assessment notice that contains both the market value and assessed value, along with an estimate of your property tax bill. For example, the median home price in Black Diamond is $706,000, with a median tax bill of $6,169. The $6,169 median tax bill is higher than the national median property tax bill of $2,400.
Property Tax Assessment Values Across Black Diamond, King County, Washington
Source: Ownwell
$275,000
$3,858,750
$7,442,500
Median Black Diamond Market Value
$706,000
Median King County Market Value
$774,000
Median Washington Market Value
$501,600
Median United States Market Value
$274,101
Property Tax Assessment Values Across Black Diamond, King County, Washington
| Zip | 10th Percentile | 25th Percentile | Median Home Price | 75th Percentile | 90th Percentile |
|---|---|---|---|---|---|
| 98010 | $436,000 | $558,000 | $706,000 | $853,000 | $1,340,600 |
Source: Ownwell
Save on Your Property Taxes and More With Ownwell
$774
Average Annual Tax Savings
Property Tax Bills Across Black Diamond, King County, Washington
Property tax bills in Black Diamond are based on the assessed value of a home and the local tax rates set by taxing districts in King County. When a property’s market value rises, the assessed value can rise too, which can increase the tax bill. For a home with a median home price of $706,000, the tax burden can be significant, especially when compared with the national median property tax rate of 1.02% and the national median property tax bill of $2,400.
Homeowners in Black Diamond often see bills that vary widely depending on location and valuation. The 25th percentile tax bill is $4,905, while the 75th percentile is $7,715 and the 90th percentile reaches $13,104. Even within the same area, differences in assessed value and exemptions can affect what a homeowner pays.
Ownwell helps homeowners lower their property tax bills by identifying overassessments, filing appeals, and pursuing exemptions when available. That can mean real savings for homeowners facing high property taxes in Black Diamond.
Median Black Diamond Tax Bill
$6,169
Median King County Tax Bill
$7,644
Median Washington Tax Bill
$4,512
Median United States Tax Bill
$3,209
Property Tax Bills Across Black Diamond, King County, Washington
| Zip | 10th Percentile | 25th Percentile | Median Tax Bill | 75th Percentile | 90th Percentile |
|---|---|---|---|---|---|
| 98010 | $3,753 | $4,905 | $6,169 | $7,715 | $13,104 |
Source: Ownwell
Save on Your Property Taxes and More With Ownwell
$774
Average Annual Tax Savings
Don't miss the deadline to appeal!
Dates | |
|---|---|
| Appeal Deadline | July 1 |
| Tax Bill | |
| Issued | February 10 |
| Due Date #1 | April 30 |
| Due Date #2 | October 31 |
Links | |
|---|---|
| King Tax Assessor | |
| Phone | (206) 296-7300 |
| Website | blue.kingcounty.com |
| assessor.info@kingcounty.gov | |