You get the repair estimate back after an accident, and somewhere in the fine print is a term you weren’t expecting: “non-OEM part,” or “aftermarket bumper cover.” Is that a downgrade? Is it even legal for your insurer to use parts that didn’t come from your car’s original manufacturer? In California, the answer is more regulated than most drivers realize — and knowing the rules can change how you handle the next estimate that lands in your inbox.

What “OEM” and “aftermarket” actually mean

OEM stands for Original Equipment Manufacturer — a part made by (or for) the company that built your car. An OEM bumper for a Honda Accord comes from Honda’s own supply chain, built to the exact specs of the part it’s replacing.

Non-OEM aftermarket parts are made by a different manufacturer to fit the same vehicle. They’re not counterfeit or automatically low-quality — some aftermarket parts are CAPA-certified (Certified Automotive Parts Association) and built to comparable standards — but they didn’t come from your car’s manufacturer, and quality can vary more than it does with OEM parts.

Insurers often prefer aftermarket parts because they’re cheaper, which keeps claim payouts lower. That’s not illegal — but California law puts real limits on how that preference can be applied to your repair.

What California law actually requires

Under California Business and Professions Code §9875–9875.2, if your repair estimate calls for non-OEM aftermarket crash parts, the shop or insurer must tell you in writing, before repairs begin. The estimate has to clearly identify each aftermarket part along with the name of the manufacturer or distributor that made it — not just “aftermarket part,” but which company.

On top of that, the law requires a specific disclosure, printed in at least 10-point type, that reads essentially:

“This estimate has been prepared based on the use of crash parts supplied by a source other than the manufacturer of your motor vehicle. Any warranties applicable to these replacement parts are provided by the manufacturer or distributor of the parts, rather than by the original manufacturer of your vehicle.”

If your estimate doesn’t include that disclosure anywhere and it’s using non-OEM parts, that’s worth asking about directly.

Can your insurer force the shop to use aftermarket parts?

Your insurer can request or specify aftermarket parts in the estimate — that part is legal. What they can’t do is use pricing as a backdoor way of controlling which shop you use. Under California Insurance Code §758.5(b)(3), an insurer can’t refuse to pay a reasonable price for parts or repairs just because you chose a shop outside their preferred network. If an insurer is effectively steering you toward a specific shop by lowballing every other estimate, that crosses into a violation.

The California Department of Insurance has also gone after vaguer, softer-sounding labels some insurers used to describe non-OEM parts — terms like “Alt-OEM,” “Opt-OEM,” or “Surplus-OEM.” The department’s position is that this kind of language is deceptive: a part is either OEM or it’s non-OEM aftermarket, and insurers are expected to call it what it is rather than dress it up.

Does using aftermarket parts affect your warranty?

This is where the fine print really matters. If a non-OEM part is used, the warranty on that specific part comes from whoever made or distributed it — not from your car’s manufacturer. In practice, that means: ask the shop directly what warranty applies to the aftermarket part itself, separately from whatever warranty the shop offers on its labor. A shop’s own lifetime warranty on workmanship doesn’t automatically extend to cover a part-quality issue with a third-party manufacturer’s product.

What to ask before repairs begin

A few direct questions to your shop or insurer can clear up most of the confusion before it becomes a problem after the fact:

Is this estimate using OEM or non-OEM aftermarket parts, and which specific parts fall into each category? Who manufactures the aftermarket parts being proposed, and are they CAPA-certified? What warranty applies to the aftermarket parts specifically, separate from the shop’s labor warranty? And — since you have the legal right to choose your own repair shop in California regardless of what your insurer recommends — has the shop given you a written estimate that includes the required disclosure language if aftermarket parts are involved?

You’re not being difficult by asking these questions. It’s exactly the information California law says you’re supposed to receive before the work starts.

If something doesn’t add up

If an insurer is using vague terminology, refusing to disclose which parts are aftermarket, or seems to be pressuring you toward a specific shop through pricing games, you can file a complaint with the California Department of Insurance’s Claims Services Bureau, or call their Consumer Hotline at 800-927-4357. This article is general information, not legal advice — for a specific dispute over your claim, it’s worth talking to the Department of Insurance directly or consulting an attorney who handles insurance claims.