To protect public health, we set emission standards for vehicles registered in Washington. Vehicle pollution causes health problems, such as cancer and asthma, and also contributes to climate change.
Committed to cleaner vehicles
In 2005, the Legislature adopted the Clean Car Law, requiring new cars to comply with California vehicle emission standards starting in 2009. Since 1971, California has had a waiver under the federal Clean Air Act to set emission standards that are more protective than the national standards set by EPA. The federal Clean Air Act allows states to adopt the federal standards or California's standards. Washington is one of 14 states, plus the District of Columbia, that chooses to follow California’s lead.
In 2018, EPA proposed to weaken the national vehicle emission standards by freezing emission improvements for model years 2021 through 2025. In response, California updated its rules to uphold the more protective standards. In December 2018, we adopted a rule that keeps Washington in line with California, ensuring that vehicles sold in Washington continue to meet the more protective emission standards.
This rule includes cars and light-duty trucks. New vehicles that do not meet Washington's vehicle emission standards cannot be registered, licensed, rented, or sold here — even if they meet federal standards. It is your responsibility to make sure your car meets the state standards.
What do you have to do differently?
If you are buying a new car in Washington, you don't have to do anything — because dealers can only sell vehicles that meet California's (and Washington's) vehicle emission standards. If you buy a vehicle with less than 7,500 miles that doesn't meet the California and Washington standards, you can't register that vehicle in Washington. Used vehicles with more than 7,500 miles can be registered.
Fourteen other states, including Oregon and California, have the same vehicle emission standards. If you buy a 2009 or newer model car in one of those states, it will meet state standards.
How do I know if a car meets Washington's standards?
For a new vehicle to meet Washington's standards, it must be California, or 50-state certified. Check the emission label found under the hood.
Which cars are the cleanest?
The amount of pollution a car puts into the air depends mainly on which emission standards it meets. It can also be affected by how you drive and maintain the car, how much fuel the car uses, and the kind of fuel used.
Passenger cars must meet certain fuel mileage standards. Generally, the better the fuel mileage, the “cleaner” the car. For example, smaller cars typically get the best fuel mileage, which also means they pollute less.
Light trucks — which include vans, small pickup trucks, and sport utility vehicles (SUVs) — are allowed to get lower fuel mileage than passenger cars. As a result, the average light truck pollutes more than the average car.
How can I find a clean car to buy?
See a list of the clean cars you can buy.
Clean driving tips
- Keep your car well maintained — A poorly-maintained engine creates more air pollution and uses more fuel. Replace oil and air filters regularly. Keep your tires properly inflated.
- Drive less — Carpool, walk, bike, ride the bus, or work from home to save money as well as reduce air pollution.
- Don’t idle your vehicle — If you stop for more than 30 seconds, except in traffic, turn off your engine. Idling for a total of 10 minutes a day uses an average of about 22 gallons of gas per year, and pollutes the air. By turning your engine off when it isn’t moving, you’ll save money on gas. Additionally, you, and others around you, won't have to breathe unhealthy exhaust fumes.
- Don’t buy more car than you need — Four-wheel drive, all-wheel drive, engine size, vehicle weight, and tire size all affect the amount of fuel your vehicle uses. The more fuel it uses, the more air pollution it causes.
Why does Washington have this law?
The Legislature passed this law to reduce air pollution and greenhouse gases from cars and trucks. More than half of Washington's residents have at least one medical condition that is made worse by air pollution. Pollution from vehicle exhaust causes health problems, such as cancer and asthma, and contributes to climate change.
Motor vehicles and other types of transportation emit more than half of the greenhouse gas emissions in Washington. These greenhouse gases cause climate change. The effects of climate change in Washington include reduced snow pack, low summer stream flows, more winter flooding, sea level rise, less water for people and agriculture, and further loss of salmon habitat.
Environmental Performance label
The Environmental Performance (EP) label is displayed on new vehicles for sale. The label provides greenhouse gas and smog emissions scores. The scoring system allows consumers to compare the vehicle’s greenhouse gas and smog emissions to other models. People can then make more informed decisions that include climate change impacts when buying a vehicle.