Sales Tax in Castle Rock, Washington in 2025

We'll walk you through how the sales tax rate is determined for Castle Rock and address some common questions you may have. We'll also cover how to collect, audit, and remit sales tax in Castle Rock.

Plus, we’ll share the best solution that will ensure you are always compliant across the entire sales tax lifecycle.

Disclaimer: Our sales tax data is updated on a quarterly basis.

Castle Rock Sales Tax Rate 2025

Castle Rock is located in Cowlitz County in Washington, United States, and has a sales tax rate of 7.90%. This includes local and state sales tax rates.

Here is the breakdown of the Castle Rock's sales tax:

Tax Jurisdiction	Sales Tax Rate
State Tax	6.50%
County Tax	1.20%
City Tax	0.20%
Combined Rate	7.90%

This rate applies to the following zip codes in Castle Rock:

District	Zip Codes	Combined Sales Tax Rate
Cowlitz County	98611	7.90%

How Does the Castle Rock Sales Tax Compare to the Rest of Washington?

Castle Rock has one of the lowest sales tax rates in Washington. At 7.90%, it is only 0.40% higher than Washington’s lowest rate (7.50% in places such as Goldendale).

To contrast, Castle Rock’s rate is 2.70% lower than Washington’s highest rate (10.60% in places such as Lynnwood).

To give you a better idea, here’s a comparison of Castle Rock sales tax rates with a few other cities in Washington:

City	Sales Tax Rates
Mukilteo	10.60%
Colfax	7.90%
Castle Rock	7.90%
Belmont	7.90%
Appleton	7.50%

What Creates Sales Tax Nexus in Castle Rock?

Castle Rock has the same nexus rules as mentioned in the Washington state tax law. It doesn’t have any separate sales tax nexus rules.

Read More: Check out this detailed guide on Sales Tax in Washington.

Any of the following conditions can create a  Washington sales tax nexus in  Castle Rock: 

• Economic Nexus: Out-of-state businesses with taxable sales of more than $100,000 in the past 12 months.

• Physical Location: Businesses with a store, office, warehouse, inventory held by a marketplace facilitator, or other places of business. Distributing taxable items using mediums other than mail or common carriers also creates a nexus.

• Employee Location: Businesses with employees or third-party representatives in the state. This also applies if the employees are engaged in soliciting sales, providing services like product training, constructing, installing, or maintaining real or tangible personal property in Washington,

• Events: Businesses that participate in more than one trade convention per year or make retail sales at any trade convention must register for sales tax. However, if the trade convention is marketed to the general public, it becomes a trade show, and participating businesses should apply for a sales tax permit.    

What Products Are Exempt from Castle Rock Sales Tax?

Sales tax exemptions for Castle Rock are granted by the Washington sales tax law. As a result, some items that enjoy sales tax exemption in Castle Rock are:

• Farm products, such as horticultural services, feed, seed, and poultry.
• Producer goods, like manufacturing machinery used for production, semiconductor materials, and computers.
• Public activities, such as road construction, ridesharing vehicles, and fuel for urban transit.
• Health-related purchases, like prescription drugs, medical devices, and blood banks.

Who Needs a Sales Permit in Castle Rock?

The state usually grants a sales permit or business license in the United States. 

So, you should register with the Department of Revenue if you fulfill any of these conditions:

• Your business needs to collect retail sales tax.
• You need city, county, or state endorsements.
• You plan to hire employees in the next 90 days.
• Your gross income is $12,000 per year or more.
• Your business is required to pay any other taxes or fees to the Department of Revenue.
• Your business requires city, county, and state endorsements.
• You are an out-of-state business that meets the sales tax nexus in Washington.

How to Collect Sales Tax in Castle Rock

Washington is a destination-based sales tax collection state. This means when you sell to a customer in Washington, you should charge the sales tax rate at the buyer’s ship-to address. 

For instance, whether your business is in Los Angeles, California or Dayton, Washington, if you sell to a buyer in Castle Rock, Washington — you should charge the sales tax in Castle Rock.

Learn more about origin-based and destination-based sales tax sourcing here.

How to File and Pay Sales Tax in Castle Rock

There are two options to file and pay Castle Rock sales tax returns:

• File and pay online: Pay through Washington MyDOR. All Washington monthly and quarterly sales tax filers are required to file and pay online.
• File and pay by mail: Businesses with waivers should file by mail. You can get your return forms at the Washington Department of Revenue website.
• Or, you can streamline your sales tax collection with Zamp. 

This way, you can leverage our accurate calculations and easy, one-click registrations to maintain compliance across the United States.