Which states require emissions testing?
27 of the 50 states and DC have a live emissions testing requirement in our records, most of them only in certain metro areas. Each state page lists where the test applies, which vehicles, how often and what it costs, with the official source quoted word for word and the date we checked it.
Required statewide
Every registered vehicle that is not exempt is tested, wherever it is kept in the state.
CaliforniaStatewide program
California's Smog Check is required every other year to renew most registrations, when a vehicle changes ownership, and when a vehicle is registered in California for the first time.
Checked Oct 6, 2026
ConnecticutStatewide program
Connecticut tests most vehicles every two years at privately owned test centers across the state.
Checked Oct 7, 2026
DelawareStatewide program
Delaware's DMV inspects vehicles itself, at its four DMV facilities and with no inspection fee.
Checked Oct 6, 2026
District of ColumbiaStatewide program
The District of Columbia requires a vehicle to pass DC DMV inspection before it can be registered, and a personal vehicle's inspection is valid for 2 years.
Checked Oct 7, 2026
MassachusettsStatewide program
Massachusetts Vehicle Check combines a yearly safety inspection and emissions test for every registered vehicle at about 1,800 licensed stations.
Checked Oct 6, 2026
New JerseyStatewide program
New Jersey inspects most passenger vehicles for emissions every two years, once they are five model years old, at state inspection lanes or licensed private inspection facilities.
Checked Oct 6, 2026
New YorkStatewide program
New York inspects every registered vehicle once a year, and most cars and light trucks get an emissions check (an OBDII scan for most newer vehicles) at the same visit, at one of thousands of licensed private inspection stations.
Checked Oct 7, 2026
Rhode IslandStatewide program
Rhode Island requires every light-duty car and truck (gas and diesel, 8,500 pounds GVWR or less) to pass a combined safety and emissions inspection at least once every 24 months.
Checked Oct 6, 2026
VermontStatewide program
Vermont inspects every motor vehicle once a year, statewide, at about 1,100 licensed stations.
Checked Oct 7, 2026
Required in some areas
Testing applies only to vehicles registered in the listed metro areas, counties or parishes.
ArizonaRequired in some areas
Arizona requires emissions tests only in the Phoenix and Tucson metropolitan areas, where a passing test is needed to register a vehicle.
Checked Oct 6, 2026
ColoradoRequired in some areas
Colorado tests most vehicles in the Denver metro area and the North Front Range.
Checked Oct 6, 2026
GeorgiaRequired in some areas
Georgia requires a yearly emissions test for gasoline cars and light-duty trucks registered in 13 metro Atlanta counties.
Checked Oct 7, 2026
IllinoisRequired in some areas
Illinois tests vehicles registered in the Chicago and Metro-East St. Louis areas.
Checked Oct 7, 2026
IndianaRequired in some areas
Indiana tests vehicles only in Lake and Porter counties in Northwest Indiana, every two years, through the Clean Air Car Check program.
Checked Oct 6, 2026
LouisianaRequired in some areas
Louisiana tests emissions only in the five-parish Baton Rouge area, as part of the yearly safety inspection for gasoline vehicles of 10,000 pounds GVWR or less.
Checked Oct 7, 2026
MaineRequired in some areas
Maine adds an emissions check to the safety inspection only for gasoline vehicles registered in Cumberland County.
Checked Oct 6, 2026
MarylandRequired in some areas
Maryland's VEIP tests vehicles registered in central and southern Maryland counties and Baltimore City every two years, when the MVA sends a notice.
Checked Oct 6, 2026
MissouriRequired in some areas
Missouri tests emissions only in the St. Louis area: St. Louis City and Jefferson, St. Charles and St. Louis counties.
Checked Oct 7, 2026
NevadaRequired in some areas
Nevada requires a yearly emissions test for vehicles based in the urban areas of Clark and Washoe counties.
Checked Oct 6, 2026
New MexicoRequired in some areas
New Mexico's only emissions testing is in Albuquerque-Bernalillo County, where vehicles up to 35 years old and under 10,001 pounds must pass a test, also at change of ownership.
Checked Oct 7, 2026
OhioRequired in some areas
Ohio E-Check tests vehicles registered in seven Northeast Ohio counties every two years.
Checked Oct 7, 2026
OregonRequired in some areas
Oregon's DEQ tests vehicles registered inside the Portland and Medford metro-area boundaries.
Checked Oct 7, 2026
PennsylvaniaRequired in some areas
Pennsylvania requires an annual emissions inspection, done with the safety inspection at private garages, for gasoline vehicles of 9,000 pounds GVWR or less registered in the counties of its Philadelphia, Pittsburgh, South Central and Northern regions.
Checked Oct 6, 2026
TexasRequired in some areas
Texas requires an annual emissions inspection for gasoline vehicles 2 through 24 years old registered in the Houston-Galveston-Brazoria and Dallas-Fort Worth areas, Travis, Williamson and El Paso counties, and Bexar County (San Antonio) joins on November 1, 2026.
Checked Oct 7, 2026
UtahRequired in some areas
Utah requires emissions inspections in five counties: Cache, Davis, Salt Lake, Utah and Weber.
Checked Oct 7, 2026
VirginiaRequired in some areas
Virginia requires emissions inspections only for vehicles garaged in Northern Virginia: five counties and five cities.
Checked Oct 7, 2026
WisconsinRequired in some areas
Wisconsin requires emissions tests for vehicles kept in seven southeastern counties: Kenosha, Milwaukee, Ozaukee, Racine, Sheboygan, Washington and Waukesha.
Checked Oct 6, 2026
Changing now
A repeal is pending or the program is on hold. Read the state page before you skip a test.
New HampshireProgram suspended
New Hampshire's vehicle inspection program, which included the OBD emissions check, is suspended until further notice.
Checked Oct 6, 2026
North CarolinaRequired now; repeal pending
North Carolina still requires an on-board diagnostic emissions inspection, with the annual safety inspection, for vehicles registered in 19 counties.
Checked Oct 7, 2026
Not required
No emissions test is needed to register a vehicle.
FloridaNo emissions testing
Florida has no vehicle emissions testing program: no emissions inspection is needed to register or renew a car there.
Checked Oct 6, 2026
IdahoProgram ended
Idaho no longer requires vehicle emissions testing.
Checked Oct 7, 2026
MichiganNo emissions testing
Michigan has no vehicle emissions testing program for registration.
Checked Oct 6, 2026
TennesseeNo emissions testing
Tennessee no longer has vehicle emissions testing.
Checked Oct 6, 2026
WashingtonProgram ended
Washington's emission check program ended on January 1, 2020, after 38 years.
Checked Oct 6, 2026
Also without emissions testing
Alabama, Alaska, Arkansas, Hawaii, Iowa, Kansas, Kentucky, Minnesota, Mississippi, Montana, Nebraska, North Dakota, Oklahoma, South Carolina, South Dakota, West Virginia, Wyoming.
Source: “The following states do not have emissions testing: Alabama, Alaska, Arkansas, Florida, Hawaii, Idaho, Iowa, Kansas, Kentucky, Michigan, Minnesota, Mississippi, Montana, Nebraska, North Dakota, Oklahoma, South Carolina, South Dakota, Tennessee, Washington, West Virginia and Wyoming.” (Colorado Division of Motor Vehicles: Emissions, checked Oct 6, 2026)
Emissions testing by state: questions
How many states require emissions testing?
Our records show 27 of the 50 states and DC with a live emissions testing requirement (statewide, in some areas, or with a repeal still pending). Each state page quotes the agency's own words and the date we checked them.
Which states have no emissions testing?
Alabama, Alaska, Arkansas, Florida, Hawaii, Idaho, Iowa, Kansas, Kentucky, Michigan, Minnesota, Mississippi, Montana, Nebraska, North Dakota, Oklahoma, South Carolina, South Dakota, Tennessee, Washington, West Virginia, Wyoming.
Is emissions testing statewide or by county?
Most states test only where the air does not meet federal standards, usually big metro areas, so the rule depends on the county where the vehicle is registered. A few states and DC test everywhere.