Dyed diesel

Dyed diesel is fuel with red dye added to show there are no federal or state fuel taxes paid. Other industry names for dyed diesel are: marked fuel, farm fuel, “red dyed” diesel.

Common uses

Common uses of dyed diesel are non-highway farming equipment, construction equipment, generators, and marine vessels.

Using dyed diesel

Dyed diesel users must have a license. This license allows approved government agencies and organizations to use dyed special fuel (diesel or biodiesel) when operating licensed motor vehicles on public roadways. The Internal Revenue Services (IRS) approved users are:

  • Public school districts
  • Nonprofit educational organization
  • Government agencies

Legal use

  • Tractors and farm equipment (“Q” decal vehicles) used within 25 miles of the registered address
  • Construction equipment
  • Stationary engines, such as a generator or welders
  • Marine vessels

Illegal use

It’s illegal to use dyed diesel in vehicles that drive on Washington State public roadways or highways. Examples of illegal use include:

  • Operating a farm vehicle, registered with a “Q” decal, with dyed diesel beyond the 25 mile radius.
  • Having dyed diesel in the fuel tank of a licensed vehicle.
  • Fueling a licensed vehicle with dyed diesel from your bulk storage tank (both the vehicle and the tank are subject to penalties).
  • Using a farm vehicle that is registered in Canada and filled with “marked fuel” on United States highways.

Penalties for illegal use of dyed diesel

Each violation will result in a fine of $10/gallon or $1,000, whichever is greater.


  • If you have 3 registered vehicles, each with a 20-gallon capacity, you may be fined $3,000. (3 vehicles x $1,000 minimum fine = $3,000)
  • If you fuel a licensed vehicle from your own 150-gallon dyed diesel slip tank or bulk storage tank, you may be fined for both the tank and the vehicle:
    • $1,500 for the bulk storage tank ($10 x 150 gallons = $1,500)
    • and
    • $1,000 for the vehicle tank ($1,000 minimum fine)

Investigation and enforcement

Fuel Tax Evasion Unit

The Fuel Tax Evasion Unit is a partnership between us and the Washington State Patrol (WSP). The unit investigates fuel tax evasion, captures data, and takes phone calls from the tip line, 800-497-FUEL (800.497.3835).

Washington State Patrol enforcement

WSP conducts thousands of “dips” to check fuel tanks for dyed fuel and determine if the operator is using the fuel illegally. If a violation occurs, the operator will receive a fine, which may appear on his or her record as a felony or misdemeanor.

How to report suspected fuel tax evasion

You can report fuel evasion by:

  • Phone: 800-497-FUEL (800.497.3835)
  • Email: evasion@dol.wa.gov
  • Mail to:
    Fuel Tax Investigations Unit
    Department of Licensing
    PO Box 9228
    Olympia WA 98507-9228

You may remain anonymous. If you leave your name and phone number, a task force member will call you back. All information you give will be investigated and remain confidential.

More information about dyed diesel

Related laws and rules

Related information

Questions? Need help?

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