Price
Call for price
Hours
Open Mon–Sat
Station type
Test & Repair
Appointments
Walk-ins welcome
Hours
- Monday
- 9 AM – 5 PM
- Tuesday
- 9 AM – 5 PM
- Wednesday
- 9 AM – 5 PM
- Thursday
- 9 AM – 4:30 PM
- Friday
- 9 AM – 5 PM
- Saturday
- 9 AM – 5 PM
- Sunday
- Closed
Good to know
Languages
English
Payment
Credit Card, Debit Card, NFC/Contactless
What to expect at Clayton Treat Automotive
Clayton Treat Automotive is licensed by the Bureau of Automotive Repair as a Test & Repair smog station in Concord, so it can run the inspection and, if your car fails, diagnose and fix it in the same shop. It is STAR certified, so it can test vehicles the DMV directs to a STAR station, including gross polluters.
Walk-ins are welcome. Most smog checks take 15 to 30 minutes, and most visits are closer to 20.
What to bring
Your registration or DMV renewal notice
It says whether the car needs a STAR station.
The car, with the check engine light off
On a 2000-or-newer car, a lit check engine light fails the test on its own.
A way to pay
The $8.25 state certificate is paid on top of the test when the car passes, unless the station's price or coupon includes it.
What if I fail?
- Clayton Treat Automotive can diagnose and repair the problem in the same shop, then retest the car.
- Each station sets its own retest price, so ask before the first test.
- BAR's Consumer Assistance Program pays up to $1,450 toward emissions repairs for income-eligible owners.
4300 Clayton Rd, Concord, CA 94521
Get directions →Hours
- Monday
- 9 AM – 5 PM
- Tuesday
- 9 AM – 5 PM
- Wednesday
- 9 AM – 5 PM
- Thursday
- 9 AM – 4:30 PM
- Friday
- 9 AM – 5 PM
- Saturday
- 9 AM – 5 PM
- Sunday
- Closed
Also listed on
Other stations near Clayton Treat Automotive
Nearby cities in Contra Costa County
Questions about Clayton Treat Automotive
Clayton Treat Automotive is open Monday 9 AM to 5 PM; Tuesday 9 AM to 5 PM; Wednesday 9 AM to 5 PM; Thursday 9 AM to 4:30 PM; Friday 9 AM to 5 PM; Saturday 9 AM to 5 PM. Closed Sunday. Hours can change on holidays, so call ahead if you are cutting it close.
Clayton Treat Automotive accepts Credit Card, Debit Card, NFC/Contactless.
Google lists the following accessibility features at Clayton Treat Automotive: wheelchair accessible entrance, wheelchair accessible parking.
Clayton Treat Automotive has held a BAR smog license since 1999. You can verify the license status at bar.ca.gov.
Clayton Treat Automotive has not published a price on SmogCheckDeals. The Bureau of Automotive Repair puts the statewide average at $69.16 as of August 2026, about $65 for a 2000-or-newer vehicle and $73 for 1999-or-older, plus the $8.25 certificate fee. Call (925) 682-4300 for a quote.
Clayton Treat Automotive does not take online bookings here, but walk-ins are welcome. Call (925) 682-4300 to check the wait.
Staff at Clayton Treat Automotive speak English.
The closest alternatives in Concord are Clayton Auto Service (0.7 mi) and Certified Smog (2.0 mi). Both are listed further up this page with their ratings and hours.
How we get this data: BAR licenses and STAR status, Google hours and ratings, coupons published by the station.
Verify this station’s license and STAR standing at bar.ca.gov.
Own this shop? Add photos
BAR field office: Hercules • Licensed since 1999