Answer: Most vehicles in Eureka and Humboldt County need a Smog Check every two years to renew DMV registration.
First time due
Humboldt Exeption: If your Eureka/Humboldt ZIP is in a Change‑of‑Ownership area, you generally will not be asked for a biennial renewal test – you’ll typically only need a Smog Check at title transfer and for first‑time California registration.
New‑car Exemption: For the first eight model years, most gasoline and hybrid vehicles don’t test at renewal and instead pay a smog abatement fee when they are in biennial testing areas
Other times required
A Smog Check can also be required at change of ownership and when registering an out‑of‑state vehicle in California for the first time, as specified by DMV notices.
Always follow the exact language on your renewal notice, including any instruction to use a STAR‑certified station.
Always go by your DMV renewal notice; it reflects your registered ZIP’s program area and whether a STAR station is required.
Exempt vehicles
Gasoline vehicles from model year 1975 and older, motorcycles, and fully electric vehicles are exempt from California’s Smog Check program.
Diesel vehicles from 1997 and older or those over 14,000 lbs GVWR are not included in the standard Smog Check program under current rules.
Diesel rules
Diesel vehicles model year 1998 and newer with a GVWR of 14,000 lbs or less generally require a Smog Check for renewal on the same biennial schedule.
Your DMV notice will indicate when a diesel inspection is due and whether a specific station type is required.
STAR stations explained
If your renewal notice says “at a STAR station,” you must use a shop that meets higher performance standards set by the Bureau of Automotive Repair for testing quality and oversight.
Regular Smog Check stations can test vehicles not flagged for STAR, while STAR stations handle vehicles identified by DMV for enhanced oversight.
Readiness monitors update (2025)
Effective October 1, 2025, BAR adopted new OBD‑II readiness rules requiring that all applicable readiness monitors be set for a vehicle to pass, with limited case‑by‑case exceptions.
The updated standard is being phased in to ensure practical implementation, so verify monitors are complete after repairs or a battery disconnect before coming in.
Get it done in Eureka
5 Rivers Auto offers fast, reliable Smog Checks with walk‑ins welcome at 1329 4th Street in Eureka for local drivers throughout Humboldt County.
Smog service is offered for $65, and you can reserve a time through our online appointment system if you prefer to book ahead.