A CARB compliant generator is a portable gas-powered unit whose engine has been certified to meet the California Air Resources Board’s emission limits for small off-road engines rated at 19 kilowatts or less. Those limits are stricter than federal EPA rules and cover both tailpipe exhaust and fuel vapor leaks. You need one if you’re buying a new portable generator in California or in another state that has adopted California’s small-engine standards. If you already own a non-certified generator, you can keep using it.
What Makes a Generator CARB Compliant
Certification comes down to hardware the manufacturer builds into the unit, not something the owner adds later. A CARB-certified engine carries a catalytic converter inside the muffler assembly to break down carbon monoxide, unburned hydrocarbons, and nitrogen oxides before they leave the exhaust. The engine itself runs leaner, with tuned ignition timing and, on some higher-end models, electronic fuel injection.
The second half of certification is evaporative control. Gasoline vapors can seep through fuel lines and tank walls even when the generator is sitting idle in your garage. Compliant units use low-permeation fuel lines, a sealed fuel cap, and a carbon canister that captures those vapors instead of releasing them into the air.1California Air Resources Board. California Code of Regulations Title 13 Division 3 Chapter 15 Article 1 A generator has to pass both exhaust and evaporative testing to earn CARB approval.
The underlying rules sit in California Code of Regulations Title 13, Sections 2400 through 2409.2Cornell Law Institute. California Code of Regulations Title 13 Division 3 Chapter 9 Beginning with model year 2024, CARB tightened the exhaust limits by 40 to 90 percent compared with previous standards.3California Air Resources Board. CARB Approves Updated Regulations Requiring Most New Small Off-Road Engines Be Zero Emission by 2024 Diesel generators and large stationary commercial units fall outside this program.
Where You Actually Need One
Every portable generator rated at or below 19 kilowatts sold in California has to be CARB certified. Retailers, including online sellers, are blocked from shipping non-compliant units to California addresses, and most major marketplaces enforce that automatically.4California Air Resources Board. California State of Emergency January 7, 2025 – Sale, Offer for Sale, and Importation of US EPA Certified Portable Generators into California
California is the only state allowed to write its own emission rules for nonroad engines, but other states can adopt California’s standards wholesale, and a number have done so.5US EPA. Vehicle Emissions California Waivers and Authorizations That’s why retailers label portable generators as either “49-state” (meets federal EPA standards only) or “50-state” (also meets CARB standards). If your state has adopted California’s small-engine rules, a 49-state unit won’t be legal for sale there. A 50-state unit is legal everywhere, which is why many buyers choose CARB-compliant generators even in states that don’t require them. You never know when you’ll move, travel with the unit, or try to resell it.
How to Verify Certification Before You Buy
Two things prove a generator is actually certified rather than just marketed that way.
The first is the emission control information label. Every CARB-certified engine carries a permanent label on the engine block or crankcase, placed where it stays visible after the engine is installed in the equipment. The label has to be metal or plastic, affixed so it can’t be removed without being destroyed, and printed in contrasting sans-serif text. Required information includes a heading such as “Emission Control Information,” the manufacturer’s name, the emission control system identification, and maintenance specifications.6Cornell Law Institute. California Code of Regulations Title 13 2404 – Emission Control Labels If you can’t find this label on a unit you’re inspecting, the generator almost certainly isn’t certified.
The second is the Executive Order number. CARB assigns a unique Executive Order to every certified engine family, and that number functions as the formal permit confirming the engine passed the board’s testing protocols.7California Air Resources Board. New Vehicle and Engine Certification Executive Orders You can look up issued Executive Orders through CARB’s certification database.8California Air Resources Board. Executive Orders, Certifications, and Verifications
What Fuel You Can Run
CARB-compliant generators are certified to run on gasoline with up to 10 percent ethanol (E10), which is the standard blend at California pumps.9California Air Resources Board. AB 30 Frequently Asked Questions E15, the 15-percent ethanol blend sold in some other states, is not approved for nonroad engines like generators or lawn mowers. Running it can damage fuel system components and may void the manufacturer’s emission warranty. Stick to E10 or ethanol-free fuel.
If You Already Own a Non-Compliant Generator
CARB’s rules target the point of sale, not the owner’s driveway. If you already have a gas generator that isn’t CARB certified, you’re generally allowed to keep using it. There’s no in-use restriction on existing small engines, and no ban on buying used ones.10California Air Resources Board. Emergency Backup Generators The tighter 2024 standards and the changes coming after them apply to new equipment at the manufacturing and retail level.3California Air Resources Board. CARB Approves Updated Regulations Requiring Most New Small Off-Road Engines Be Zero Emission by 2024
Local air districts can set their own usage rules on top of that, especially for commercial operations. CARB recommends checking with the air district where you plan to use the generator to see whether it has imposed any usage limits or permit requirements.10California Air Resources Board. Emergency Backup Generators For a homeowner running a generator during a power outage, the baseline rule holds.
The 2028 Zero-Emission Deadline
Starting with model year 2028, the combined hydrocarbon-plus-nitrogen-oxide limit for new portable generators drops to 0.00 g/kWh across every engine size.11Cornell Law Institute. California Code of Regulations Title 13 2403 – Exhaust Emission Standards and Test Procedures In practice, that means new gas-powered portable generators can no longer be certified for sale in California. Manufacturers are expected to shift to battery-powered portable power stations, and CARB set up a credit program for model years 2023 through 2026 that lets companies earn credits by certifying zero-emission units early and apply them against deficits once the mandate takes effect.
Your existing gas generator doesn’t become illegal in 2028. The rule governs manufacturing and sales of new units, and used equipment can still change hands. The practical effect for a shopper today is that any CARB-compliant gas generator you buy now is part of the last generation of combustion-powered portable units that will be available new in California. If you expect to run the same generator ten years from now, that’s worth weighing against a battery-based alternative while you’re deciding.