---
title: "Clean Truck Check Testers in Napa County, CA (11)"
description: "11 CARB-credentialed Clean Truck Check testers in Napa County, California, across 1 city. 11 offer mobile testing. Search by city, see phone numbers and…"
url: "https://ctcfinder.com/testers/napa-county/"
updated: "2026-11-01"
publisher: "CTC Finder (independent directory, not affiliated with CARB)"
---

# Clean Truck Check testers in Napa County, California

11 testing businesses in 1 city; 11 offer mobile testing, 6 do smoke opacity tests, 8 test motorhomes.

> CTC Finder is an independent directory, not affiliated with CARB. Tester data: CARB Clean Truck Check public tester list, last checked November 1, 2026. Confirm services, hours and prices with the tester.

## City pages

- [Napa](https://ctcfinder.com/testers/napa-county/napa/) — 11 listings




## 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](https://ctcfinder.com/guide/cost/).