Emissions Testing in Delaware

Testing Requirements

Current Testing Requirements in Delaware

Delaware operates a statewide combined safety and emissions inspection program. Both the safety and emissions inspections are conducted at the same time during a single visit to a DMV inspection facility. The emissions program operates under two regulations: one for Sussex County and one for Kent and New Castle counties, though both were aligned in 2023 to follow the same standards. Gasoline vehicles model year 1996 and newer receive an OBD-II inspection. Diesel vehicles model year 1997 and newer under 8,500 pounds also receive an OBD-II test. Vehicles from 2008 and newer with a gross vehicle weight between 8,501 and 14,000 pounds receive the OBD-II test in all three counties. Older gasoline vehicles receive a curb idle tailpipe test and a gas cap pressure test. All vehicles also undergo a visual inspection of emissions control components, including the catalytic converter.

Who Needs an Emissions Test

Most gasoline and diesel vehicles registered in Delaware with a gross vehicle weight rating of 8,500 pounds or less must pass both a safety and emissions inspection. Vehicles from 2008 and newer weighing between 8,501 and 14,000 pounds are also subject to the OBD-II emissions test. Vehicles within their first seven model years are exempt from both safety and emissions inspection if they are being titled in Delaware for the first time and weigh less than 10,000 pounds. After the seven-year exemption expires, vehicles enter the biennial testing cycle. Gasoline vehicles model year 1968 and older are exempt from emissions testing but still require a safety inspection. Diesel vehicles model year 1997 and older are also exempt from the emissions portion. Motorcycles are exempt from emissions testing. All out-of-state vehicles being registered in Delaware for the first time must undergo a full inspection at a DMV facility.

How Often Tests Are Required

Safety and emissions inspections are required every two years in Delaware. Testing is tied to registration renewal. The DMV sends electronic or phone renewal notices at 90, 60, and 30 days before registration expiration. Vehicles may be inspected up to 90 days before registration expires without changing the expiration date. There is no annual testing requirement for any vehicle type.

Where Emissions Testing Is Required

Emissions testing is required statewide in all three Delaware counties: New Castle, Kent, and Sussex. There are no county or regional exemptions. The same testing standards now apply across all three counties following regulatory amendments adopted in 2023. All eligible vehicles registered anywhere in Delaware must pass the combined safety and emissions inspection.

What Happens During the Test

The inspection has two components performed during a single visit. The safety inspection checks brakes, lights, tires, steering, windshield, mirrors, horn, and other critical equipment. The emissions inspection begins with a visual check confirming the catalytic converter is present and intact. For model year 1996 and newer gasoline vehicles and model year 1997 and newer diesel vehicles under 8,500 pounds, a technician connects to the OBD-II port and checks for diagnostic trouble codes, readiness monitor status, and the malfunction indicator lamp. A lit check engine light is an automatic failure. Recently replaced batteries can cause readiness monitors to show as incomplete, which also results in failure. Drive the vehicle for several days after a battery replacement to reset the monitors before testing. Older vehicles receive a curb idle tailpipe test and a gas cap pressure leak test. The entire inspection takes about 15 to 30 minutes.

Areas in Delaware That Require Emissions Testing

All areas of Delaware require emissions testing. Cities and communities where testing applies include Wilmington, Dover, Newark, Middletown, Smyrna, Milford, Seaford, Georgetown, Lewes, Rehoboth Beach, Bethany Beach, New Castle, Bear, Hockessin, Pike Creek, Claymont, Elsmere, and Delaware City. Rural areas throughout the state follow the same requirements. The DMV operates inspection facilities in four locations: Wilmington, Delaware City, Dover, and Georgetown.

How the Emissions Test Works in Delaware

Drivers take their vehicle to one of four DMV-operated inspection facilities: Wilmington, Delaware City, Dover, or Georgetown. No appointment is needed. Drive into an inspection lane and present your vehicle registration card. A DMV technician will verify the VIN, perform the safety inspection, and then conduct the emissions test based on the vehicle's model year and fuel type. There is no charge for the inspection. If the vehicle passes both portions, it receives an inspection sticker valid for two years. If the vehicle fails the safety inspection, repairs must be completed and the vehicle must be retested. No waivers are available for safety failures. If the vehicle fails the emissions inspection, the owner receives a Vehicle Inspection Report explaining the failure. Repairs must be completed before retesting, which is also free. Retesting for emissions failures requires a return visit to a DMV facility. Waivers for emissions failures may be available if the owner has spent a minimum amount on qualifying repairs performed by a Certified Emission Repair Technician and the vehicle still cannot pass. The repair cost minimum varies by model year and county and is set by DNREC regulation. Waivers cannot be issued for visible smoke, missing emissions equipment, or tampered components. If registration is about to expire during the repair period, a temporary registration tag may be available through the DMV.