Reference Source

Vehicle emissions testing: which counties require it, in which states

For each US state that runs a vehicle emissions inspection (I/M) program: which counties require testing, how often, which vehicles are exempt, and the test type — from the state environmental agency's own page, not a DMV content mill. The answer is county-level, not state-level, and it is moving: North Carolina asked EPA to remove all nineteen of its remaining counties (submitted October 2024), Texas is adding Bexar County (San Antonio) in 2026, and Colorado is changing test types in 2026. Georgia's program covers exactly 13 named metro-Atlanta counties; Texas covers 17 counties across four metros; Colorado covers all or part of 9 Front Range counties; California's list of 34 counties is the fact that testing there is not statewide. Some exemptions move on their own: Virginia's regulation exempts anything older than 'the current calendar year minus 24', so the cut-off year advances every January whether or not anyone republishes the page; Vermont tests the OBD system on vehicles '16 model years old or newer', and New York's OBDII window runs from 'the current year minus 25' to 'the current year minus two' — three rolling cut-offs no static listicle tracks. The north-east answers the county question differently: Vermont, New Jersey, Rhode Island, Delaware and New Hampshire inspect everywhere in the state, and in New York the county list that matters is the Diesel Emissions Metropolitan Area for heavy diesels, while light diesels take the OBDII test anywhere in the state. EPA maintains no current state/county list — only technical guidance. Utah is the clearest case for asking the question county by county: its program is run by five county health departments and they do not share one rule, so Cache County exempts vehicles less than six model years old while Salt Lake, Davis, Weber and Utah counties test them every other year, and Utah County alone tests 1998–2021 diesels. New Mexico's whole program is one county — Bernalillo — under the Albuquerque-Bernalillo County Air Quality Control Board's own regulation. Two states are recorded here as stated absences rather than omitted: Idaho repealed the state I/M requirement effective 1 July 2023, and EPA removed Tennessee's six counties from the federally-approved plan effective 16 September 2021 — though that rule's own footnote says it does not preclude counties keeping a local program, so 'Tennessee has no testing' is not quite what the source says. Two gaps are stated rather than papered over. Ohio names no county anywhere we can reach: OAC 3745-26-01(G) defines the program area by nonattainment status instead of by name, so the cadence, the twenty-five-year scope, the exemptions and the E-Check contract's June 2027 end date are recorded and the county list is not claimed. And Massachusetts carries no cadence, because the annual interval lives in 540 CMR 4.00, which no host that will serve us publishes as text; its scope and exemptions come from Cornell LII's mirror of 310 CMR 60.02 — a mirror, not mass.gov, which blocks us, and one that states it reflects amendments only through 11 August 2017. Answers 'do I need an emissions test to register my car in [county], [state]', 'is [state] getting rid of emissions testing', and 'how old does my car have to be to be exempt in [state]'. States with no program get no record unless their agency states the absence.

Records28
Sources36
Verified
Review by
Licenceunknown

3 records where two or more sources state different values. Both sides are reproduced on the record page, each with its own source and quote.

The data

StateCounties where testing is requiredVehicles covered / exemptRecent or pending changeProgram / authorityHow often
Arizonathe Phoenix and Tucson metropolitan areas
CaliforniaAlameda Butte Colusa Contra Costa Fresno Glenn Kern Kings Los Angeles Madera Marin Merced Monterey Napa Nevada Orange Sacramento San Benito San Francisco San Joaquin San Luis Obispo San Mateo Santa Barbara Santa Clara Santa Cruz Shasta Solano Stanislaus Sutter Tehama Tulare Ventura Yolo Yuba
Coloradoall or portions of Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson, Larimer, and Weld countiesowners of gasoline-powered vehicles in the Front Range area of ColoradoStarting in 2026, these Colorado drivers will have access to self-service kiosks for On-Board Diagnostics (OBD) emissions tests that will be available 24/7 at convenient locationsAutomobile Inspection and Readjustment (AIR) program
Connecticutthroughout the stateEmissions Testing Programtested every two years
DelawareThe first seven model years are exempt from emissions testingInspection and Maintenance programbiennial, requiring vehicles to pass safety and emission inspections once every other year
Georgiasources differ13-county Atlanta Metropolitan Area (Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding or Rockdale)gasoline-powered passenger vehicles registered in the 13-county Atlanta Metropolitan AreaGeorgia’s Clean Air Force
IdahoIn 2022, the Idaho Legislature passed a law to repeal the state requirement for vehicle I/M programs (e.g., emissions testing), effective July 1, 2023.Inspection and Maintenance (I/M) p rograms
Illinoisthese areas of Illinoisvehicle emissions inspection program
MarylandAnne Arundel, Baltimore City, Baltimore, Calvert, Carroll, Cecil, Charles, Frederick, Harford, Howard, Montgomery, Prince George's, Queen Anne's, and WashingtonVEIP
Massachusettsall motor vehicles registered in Massachusetts; 2. any motor vehicle owned or operated by a federal agency in Massachusetts (regardless of whether such vehicles are registered in Massachusetts); and 3. diesel vehicles with a GVWR greater than 10,000 pounds operating on Commonwealth roads but not registered in Massachusetts.Emissions Inspections
MissouriSt. Louis City St. Louis County St. Charles County Jefferson CountyGas-powered vehicles 1996 and newer or diesel powered vehicles 1997 and newerGateway VIP
Nevadathe urban areas of Clark or Washoe countyGasoline powered (regardless of weight or size)Nevada Emission Control Programemission tests each year for qualifying vehicles
New Hampshireautomated safety and emissions inspection programall passenger vehicles shall be inspected annually during the owner’s month of birth
New Jerseyinspected once every two years in New Jersey with the exception of new vehicles. New vehicles need a five-year inspection
New MexicoBernalillo countyAlbuquerque-Bernalillo County Air Quality Control Board
New Yorkdiesel vehicles registered within the Diesel Emissions Metropolitan Area (DEMA) - New York City, Nassau County, Suffolk County, Rockland County, and Westchester Countymust get an annual diesel emissions inspection
North Carolina19 countiescars and light-duty trucksSection 12.7 of Session Law (S.L.) 2023-134 (House Bill 259) of the 2023 session of the North Carolina General Assembly, passed into law October 3, 2023, will remove 18 counties from the I&M program. Section 12.13.(b) of Session Law (S.L.) 2026-41 (Senate Bill 257) of the 2026 session of the North Carolina General Assembly, passed into law July 7, 2026, will also remove Mecklenburg County from the program.Inspection / Maintenance (I/M) Programemission systems tests for cars and light-duty trucks as part of the annual safety inspection in 19 counties
Ohiosources differeach twenty-five year-old or more recent motor vehicle whose owner or lessee resides in a county that is part of a designated program areamotor vehicle inspection and maintenance programbiennial inspection for the enhanced vehicle inspection and maintenance program
Oregonthe Portland and Medford areasVehicle Inspection Programbiennial
PennsylvaniaChester, Delaware, Bucks, Montgomery and Philadelphia Counties constitute the Philadelphia Region; Allegheny, Beaver, Washington and Westmoreland Counties constitute the Pittsburgh Region
Rhode IslandModel year 1996 and newer vehicles shall undergo an OBD inspection in addition to, a gas cap inspection, and a safety inspectionAll vehicles will be subject to inspection every two years
TennesseeEPA is approving the removal of Tennessee's motor vehicle inspection and maintenance (I/M) program requirements for Davidson, Sumner, Rutherford, Williamson and Wilson Counties in Tennessee (also known as the Middle Tennessee Area) and Hamilton County (also known as the Chattanooga Area), from the federally-approved SIP.motor vehicle inspection and maintenance (I/M) program
Texassources differBrazoria, Collin, Dallas, Denton, Ellis, El Paso, Fort Bend, Galveston, Harris, Johnson, Kaufman, Montgomery, Parker, Rockwall, Tarrant, Travis, and Williamson CountiesBeginning November 1, 2026, motorists with vehicles registered in Bexar County will not be eligible to renew their vehicle's annual registration if the vehicle has not passed its annual emissions inspectionvehicle emissions inspection programannual emissions inspection
UtahCache, Davis, Salt Lake, Utah, or Weber countiesEmissions Inspection
Vermonton a statewide basisVermont’s Vehicle Emissions Inspection and Maintenance Programall motor vehicles be inspected annually
Virginiathe counties of Arlington, Fairfax, Loudoun, Prince William, and Stafford; and the cities of Alexandria, Fairfax, Falls Church, Manassas, and Manassas ParkNorthern Virginia emissions inspection program
WashingtonWashington's vehicle emission check program ended Jan. 1, 2020vehicle emission check program
Wisconsinseven counties in Southeast Wisconsin: Kenosha, Milwaukee, Ozaukee, Racine, Sheboygan, Washington and Waukesha

Where this came from

Every record above links the page it was taken from and quotes the sentence that states it. These are the 36 sources this dataset was assembled from.

Machine-readable

From your own code

Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.

pip install refsource
refsource lookup vehicle-emissions-testing-by-state jurisdiction=Arizona

npx -y refsource lookup vehicle-emissions-testing-by-state jurisdiction=Arizona

Set your AI assistant up to use this

Two files and no account. Put this in .mcp.json at the root of your project — Claude Code, Cursor, Windsurf, VS Code and Codex all read that file — and your assistant can look this dataset up instead of recalling it. The server is remote, keyless and read-only.

{
  "mcpServers": {
    "referencesource": {
      "type": "http",
      "url": "https://referencesource.org/mcp"
    }
  }
}

Add to Cursor · or, on the command line: claude mcp add --transport http referencesource https://referencesource.org/mcp --scope project

Then one line in the project's CLAUDE.md or AGENTS.md, so the assistant knows when to reach for it:

When a question needs "Vehicle emissions testing: which counties require it, in which states", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `vehicle-emissions-testing-by-state`) instead of answering from memory — every record it returns carries its source URL and a verbatim quote from that page.

What each tool does, and the servers built over single registers: Connect your AI assistant.

28 records. last verified against source . due for re-check by .

Licence. unknown