Our Tax Discovery Unit protects Washington's fuel tax system by making sure all businesses report and pay their taxes correctly. We focus on companies involved in fuel distribution and interstate trucking. We provide critical support through:
- Correcting mistakes – Reviewing filings for errors and working with businesses to fix them.
- Finding missing information – Ensuring all required details are reported to prevent revenue loss.
- Stopping tax evasion – Investigating companies that try to avoid paying fuel taxes and enforcing compliance.
- Identifying unlicensed businesses – Locating companies operating without proper registration and bringing them into compliance.
By handling these responsibilities, tax discovery keeps fuel tax reporting fair and accurate. The revenue we recover supports the upkeep and safety of Washington’s roads and highways, benefiting everyone who uses them.
Our tax discovery unit collaborates with partners at the Washington State Patrol to educate both the public and the fuel industry about tax rules.
Prorate and fuel tax fraud
We also investigate situations where fuel tax evasion is suspected and take action to enforce the law. Our team ensures everyone follows the rules, keeping the system fair and supporting the public services that depend on fuel tax revenue.
There are many ways to be out of compliance with prorate and fuel tax laws like:
- Importing fuel without paying the appropriate taxes owed in Washington.
- Blending taxable fuel with an untaxed product to increase volume.
- Using dyed diesel (untaxed) fuel in any licensed vehicle or vehicle required to be licensed.
- Acting as a fuel supplier or fuel distributor without a license.
- Acting as an International Fuel Tax Agreement (IFTA) carrier without a license.
How to file a complaint
Public involvement is key to stopping fuel tax evasion. You can file a complaint by email, fax or mail.
Please include the following:
- Copies of any documents related to your complaint
- A detailed explanation of your complaint, including:
- Dates
- Location
- Names of the business or others involved
- A description of events in the order they occurred
- Color photos of the incident (if available)
If mailing your complaint, mail to:
Tax Discovery Unit (TDU)
Department of Licensing
PO Box 9228
Olympia, WA 98501-9228
Or fax:
360-570-7045
What actions we can take
If a person or business violates prorate and fuel tax requirements or operates without a license, we may take actions against them, including:
- Financial assessments for taxes, penalties, interest or fines as applicable
- Including tax liens against real property
- License suspensions or revocations
- Referral to other agencies for action
What we can't do
We don't have the authority to resolve civil disputes, award damages, or make judicial determinations. Please seek legal advice in these situations.
