Emissions Testing by State

Some states require emissions testing or smog checks statewide, while others test only in selected metro areas. Major testing states include California, Arizona, Colorado, Texas, New York, and Maryland, along with several others that operate regional programs. The easiest way to check is to select your state in this directory and review the current 2026 rules.

A number of states have no routine emissions testing requirement for most passenger vehicles, while others limit testing to special cases or certain heavy or commercial vehicles. Because rules change and local programs can differ, select your state in the directory to see whether any emissions or smog-check requirements apply where you live.

An emissions test, often called a smog check, measures the pollutants coming from your vehicle's exhaust and verifies that key emissions-control systems are working properly. States may use OBD-II computer checks, tailpipe tests, gas-cap pressure tests, or opacity tests for diesel vehicles. Passing the test is usually required before you can renew your vehicle registration in testing areas.

Whether you need an emissions test depends on your state, your registration ZIP code, and your vehicle's model year, weight, and fuel type. Many states test only in specific counties or metro areas and exempt the newest model years. Select your state in this directory to see the exact 2026 requirements and exemptions for your vehicle.

Most emissions programs require testing every one or two years, usually tied to your registration renewal month. Some states require annual tests for older or diesel vehicles and biennial tests for newer cars. Your state notice or online lookup will show your test cycle; you can also check your state's page in this directory.

A standard emissions test or smog check usually takes 10 to 20 minutes once your vehicle is in the bay. The visit may take longer if there is a line or if your vehicle requires a dynamometer or more complex inspection. Bringing current registration and ensuring the check engine light is off can help speed up the process.

All-electric vehicles are exempt from tailpipe emissions testing nationwide because they produce no exhaust. Hybrid requirements vary by state. Many states test hybrids just like gasoline vehicles, while others exempt the newest hybrid model years for a set period. Check your state's page to see how hybrids are treated in 2026.

Several states include diesel vehicles in their emissions or opacity testing programs, especially in metro areas with air-quality concerns. Programs in states such as California, Arizona, Colorado, New York, and Maryland may require testing for certain diesel weight classes or model years. Requirements are very state-specific, so review your state page for details.

Emissions test fees range from free to $55, with most drivers paying between $20 and $35 per inspection. States like Ohio and Wisconsin offer free testing, while Rhode Island charges $55 for a combined safety and emissions inspection. California does not regulate station prices, so costs there typically range from $50 to $70. Your state page lists typical costs and whether retests are free or discounted after repairs.

Select your state in the directory to browse approved emissions testing locations by city. Each state page includes a grid of testing stations so you can quickly find a smog-check or emissions-test provider near you in any area where testing is required.

If your vehicle fails, you typically must complete emissions-related repairs and pass a retest before renewing registration. Many states offer one free retest within a set time window and may provide repair waivers or cost-based exemptions if you spend over a specified amount on documented repairs. Your state page explains the exact retest and waiver rules.

Many states exempt vehicles within the first three to seven model years from emissions testing, assuming newer vehicles produce lower emissions and already meet modern standards. The length of the new-vehicle exemption window and renewal schedule is different in each state, so check your state's rules for the current model year range.