Clean Truck Check testers in Napa County
11 testing businesses in Napa County are on CARB's public tester list, in 1 city. 11 (100%) offer mobile testing, 6 do smoke opacity tests and 8 test motorhomes.
Cities in Napa
Frequently asked questions
How many Clean Truck Check testers are in Napa County?
CTC Finder lists 11 testing businesses in Napa County from CARB's public tester list (12 credentialed testers), last checked November 1, 2026. Listing on CARB's list is optional, so the real number can be higher.
Is there mobile Clean Truck Check testing in Napa County?
Yes. 11 listed businesses in Napa County offer mobile testing, which means the tester comes to your yard. Use the Mobile filter above to see them.
How much does a Clean Truck Check test cost in Napa County?
Testers set their own prices. Published prices for an OBD test are usually $50–$135 per vehicle; smoke opacity tests for older trucks often cost more, and mobile testers may add a trip fee. See the cost guide.
Source: CARB's public Clean Truck Check tester list, last checked . Listing on CARB's list is optional for testers, so some credentialed testers are not shown. Services, hours and prices change; please confirm with the tester before you go. Something wrong? Send a correction.