Skip the auto shop - Our mechanics make house calls

What Are California's Emissions Standards?

California Emission Standards

California is one of the most heavily populated states in the country. There are more vehicles on the road there than almost anywhere else in the country (statewide). Because of this, the state has had to adopt very strict emissions standards that are actually much more comprehensive than those instituted by the Environmental Protection Agency (EPA). Automakers have started designing their vehicles to meet these standards, even if they’ll be sold somewhere else in the US. What are California emissions standards?

A look at designations

There are three tiers to California emissions standards. These denote emissions regulations in the state as they’ve changed over the years. Note: LEV stands for Low Emissions Vehicle.

  • Tier 1/LEV: This designation means that a vehicle meets the California emissions regulations through 2003 (applies to older vehicles).

  • Tier 2/LEV II: This designation means the vehicle meets California emissions regulations as enacted from 2004 through 2010.

  • Tier 3/LEV III: This designation means that the vehicle meets the state’s emissions requirements from 2015 through 2025.

Other designations

You’ll find a host of different emissions standards designations in use (they’re located on the label under the hood of your car). These include:

  • Tier 1: The oldest designation, found primarily on cars manufactured and sold in 2003 or earlier

  • TLEV: This denotes that the vehicle is a Transitional Low Emissions Vehicle

  • LEV: Stands for Low Emissions Vehicle

  • ULEV: Stands for Ultra Low Emissions Vehicle

  • SULEV: Stands for Super Ultra Low Emissions Vehicle

  • ZEV: Stands for Zero Emissions Vehicle and is only applicable to electric cars, or other vehicles that produce no emissions at all.

You’re likely to encounter these designations on vehicle labeling all over the US because automakers were required to manufacture a specific percentage of vehicles to meet California emissions standards (whether those vehicles were ultimately sold in California or not). Note that Tier 1 and TLEV designations are no longer in use, and will only be found on older vehicles.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
How to Transfer a Car Title in Idaho
In order to prove ownership of a car, you must have the title. However, when a car is sold, given away or inherited, the title needs...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...


Related questions

Q: What Are California's Emissions Standards?

California emissions standards are the highest in the nation, and exceed the EPA’s regulations. You’ll find that many vehicles sold in different parts of the country are rated for California’s emissions standards because automakers are required to manufacture a certain...

Q: Exhaust fumes in car

Hello. When you run the climate control, the vehicle takes air from around the engine and outside of the vehicle and uses it to warm or cool and cab. If there is any form of exhaust leak in the system,...

Q: Why Is it so Important That a Car Passes Emissions Testing?

Emissions testing provides several very useful functions for our daily lives. The combustion gases that come out of the tailpipes of our vehicles are comprised of carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx), carbon dioxide (CO2), and oxygen...