What states require smog checks? Quick Answer
- As of 2025, 28 states and the District of Columbia require smog checks in certain areas, including California, New York, Texas and Illinois. Smog tests are typically mandatory in high-pollution regions. Meanwhile, 22 states—like Florida, South Dakota and Alabama—do not require emissions testing.
Summary
- Even in states requiring smog checks, some vehicles are exempt
- Checks often aren’t necessary for hybrid, electric or very old cars
- If your car fails a smog check, it must be repaired before registration
Many states require vehicles to undergo periodic inspections. These inspections are designed to catch problems that could lead to car accidents or cause other safety issues. However, in several states, they have an additional purpose: making sure cars aren’t causing excessive pollution.
Here’s a closer look at which states require smog checks and what the process entails.
What Is a Smog Check?
A smog check is a test that measures how much pollution your car emits. If you're asking what is a smog check, it’s a state-required inspection aimed at reducing harmful emissions that affect public health and the environment. These checks often include inspecting your car’s tailpipe, emissions system, and onboard diagnostics. Depending on where you live, you might need one every year or two, especially if your car is older or diesel-powered.
What Vehicles Need Emissions Testing?
Not all vehicles require emissions testing. Exemptions can vary depending on the region, but these are some of the most commonly exempted vehicles:
- Electric cars
- Hybrid cars
- Very old cars from 1975 or earlier
- Very new cars, typically less than eight years old
- Very heavy vehicles weighing more than 14,000 pounds
If you aren’t sure whether your vehicle needs emissions testing, your state’s Department of Motor Vehicles should be able to give you the answer.
What States Require Smog Testing?
Based on the most recent data, 28 U.S. states and the District of Columbia require emissions testing in at least some areas. These states include:
| State | Source |
|---|---|
| Arizona | Arizona Department of Transportation |
| California | State of California DMW |
| Colorado | Colorado General Assembly |
| Connecticut | Connecticut DOT |
| Delaware | DNREC |
| District of Columbia | DC DMV |
| Georgia | Georgia’s Clean Air Force |
| Illinois | Illinois Environmental Protection Agency |
| Indiana | Indiana Bureau of Motor Vehicles |
| Louisiana | Louisiana Department of Environmental Quality |
| Maine | Maine Department of Environmental Protection |
| Maryland | Maryland DMV |
| Massachusetts | Commonwealth of Massachusetts |
| Missouri | Gateway Vehicle Inspection Program |
| Nevada | Nevada DMV |
| New Hampshire | New Hampshire DMV |
| New Jersey | New Jersey MVC |
| New Mexico | New Mexico MVD |
| New York | New York DMV |
| North Carolina | North Carolina DMV |
| Ohio | Ohio Environmental Protection Agency |
| Oregon | Oregon DEQ |
| Pennsylvania | Commonwealth of Pennsylvania |
| Rhode Island | Rhode Island DMV |
| Texas | Texas Department of Public Safety |
| Utah | Vermont DEC |
| Vermont | Vermont DEC |
| Virginia | Virginia DMV |
| Wisconsin | Wisconsin DMV |
These states may not test every vehicle or in every county, but residents in larger cities or high-pollution areas are usually required to get regular checks.
The required smog check frequency can vary significantly between states. For example, Maryland car inspection requirements only require a vehicle to pass an inspection before it is sold or before it is registered in Maryland.
What Happens if Your Car Fails a Smog Test?
For many people, getting their vehicle smog tested seems like a formality. But what happens if your car fails?
If your vehicle doesn’t meet your state’s emissions requirements, you may not be able to register it or renew your registration until the problem has been fixed. Once you have taken the car to a mechanic, you generally must then have it rechecked.
What States Don't Require Smog?
If you're wondering what states don't require smog, you're in luck if you live in one of 22 states that currently don’t mandate any emissions testing. These include:
| State | State | State |
|---|---|---|
| Alabama | Kentucky | Oklahoma |
| Alaska | Michigan | South Carolina |
| Arkansas | Minnesota | South Dakota |
| Florida | Mississippi | Tennessee |
| Hawaii | Montana | Washington |
| Idaho | Nebraska | West Virginia |
| Iowa | North Dakota | Wyoming |
| Kansas |
In these states, you can register your car and drive without a smog check—unless local city or county ordinances say otherwise.
Why Smog Checks Matter
Even if your state doesn’t require one, smog checks serve an important role. They help catch engine or exhaust problems early, protect the environment, and keep your car running efficiently. If you’re selling your car or moving, knowing what states require a smog test can save you time and fines.
The Importance of Following Smog Test Laws
Understanding what states require smog checks is key if you're relocating or buying a vehicle across state lines. Rules vary widely, and failing to meet your state’s requirements can lead to registration issues or penalties.
If you live in a state that requires smog tests, stay on top of your testing schedule to keep your vehicle road-legal and environmentally friendly. And if you're in a no-test state, you’re off the hook—but it’s still smart to keep your car in clean running condition.
Smog check laws are usually relatively straightforward. However, if you’ve been accused of fraud while trying to get your car to pass or are facing other legal issues, you should contact an attorney as soon as possible.
Not sure how to find a lawyer? ConsumerShield can help. We connect people like you with reliable lawyers nearby. Complete our contact form for a free, no-obligation case review today.
