# Connecticut — Vehicle emissions testing: which counties require it, in which states

For Connecticut, counties where testing is required is throughout the state; how often is tested every two years; program / authority is Emissions Testing Program, verified against its source on 2026-08-19.

- **State:** Connecticut _(our reading, not quoted from the source)_
- **Counties where testing is required:** throughout the state _(verified: appears in the quote below)_
- **How often:** tested every two years _(verified: appears in the quote below)_
- **Program / authority:** Emissions Testing Program _(verified: appears in the quote below)_
- **Vehicles covered / exempt:** 2001 and newer gasoline-powered and 2001 and newer diesel-powered vehicles with the Gross Vehicle Weight Rating (GVWR) less than 8,501 pounds _(per ctemissions.com, not stated by the source above)_

## What the source says

> Vehicles are tested every two years by a network of more than 200 privately owned automotive service facilities located at convenient locations throughout the state.

## What ctemissions.com says

> Vehicles subject to OBD testing include 2001 and newer gasoline-powered and 2001 and newer diesel-powered vehicles with the Gross Vehicle Weight Rating (GVWR) less than 8,501 pounds.

Source: https://www.ctemissions.com/types-of-vehicle-testing

## Source

- https://www.ctemissions.com/
- https://www.ctemissions.com/types-of-vehicle-testing

Last verified: 2026-08-19. Review by: 2027-08-19.
Part of [Vehicle emissions testing: which counties require it, in which states](https://referencesource.org/vehicle-emissions-testing-by-state/).