Idaho State Tax Commission

Vehicle inspections to begin for dyed (untaxed) diesel

Fuel inspection 

Effective January 1, 2021, the Idaho State Police (ISP) and Idaho Transportation Department (ITD) will perform visual inspections of fuel from the main supply tank of qualifying vehicles. When dye is present in the fuel, they’ll photograph the samples and a penalty will be assessed. (See Idaho Code section 49-676.) 

  • Qualifying vehicles are commercial vehicles over 26,000 lbs. gross vehicle weight 
  • ITD Port of Entry inspectors may inspect fuel and tanks during a routine fixed or roving port inspection 
  • ISP troopers may inspect fuel and tanks as a secondary action during a traffic stop  


A civil penalty will be assessed if: 

  • You refuse to allow inspection, or 
  • There is visible evidence of dye in the visual inspection 

The penalties are as follows: 

  • $250 for the first offense 
  • $500 for the second offense  
  • $1,000 for a third and any subsequent offenses  
  • $1,000 for refusing the inspection 


For questions about billing and penalties, please call the Idaho State Tax Commission at (800) 972-7660. 

For questions about testing or testing locations, please call the ISP at (208) 884-7220 or ITD at (208) 334-8427. 


See Idaho Code sections 49-676, 63-2425, 63-2460, and 40-510. 




Posted 12-30-2020
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This information is for general guidance only. Tax laws are complex and change regularly. We can't cover every circumstance in our guides. This guidance may not apply to your situation. Please contact us with any questions. We work to provide current and accurate information. But some information could have technical inaccuracies or typographical errors. If there's a conflict between current tax law and this information, current tax law will govern.