Clayton Treat Automotive

Yes. Clayton Treat Automotive is STAR certified with the California Bureau of Automotive Repair, so it can test vehicles the DMV directs to a STAR station, including gross polluters.

No. Clayton Treat Automotive is licensed as a Test & Repair station. This station can run your smog test and, if the vehicle fails, diagnose and repair it in the same shop.

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.

Yes. Clayton Treat Automotive accepts walk-ins, so you can drive in without booking ahead.

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.

Bring the car, your registration or DMV renewal notice, and a way to pay. Most smog checks take 15 to 30 minutes, and most visits are closer to 20.

Because Clayton Treat Automotive is a Test & Repair station, it can diagnose and repair the problem in the same shop, then run the free retest within 30 days. If the repair bill is steep, California's Consumer Assistance Program covers up to $1,200 of emissions repairs for qualifying owners.

The closest alternatives in Concord are Clayton Auto Service (0.7 mi) and Green Star Smog (2.0 mi). Both are listed further up this page with their ratings and hours.