Summary
The California Supreme Court unanimously held that the Government Claims Act, the state's uniform rulebook for money claims against local governments, occupies the entire field of how those claims must be presented. A city cannot force a business to finish its own multi-step administrative refund process before filing a claim for a local tax refund. Cities have used that extra process for years to slow down and defeat refund suits. After Tesoro, they can't.
If your business pays a tax to a California city and believes the city got the number wrong, you’d expect a straight path to challenge it. For years, some cities made that path anything but straight. They stacked their own refund procedures on top of the state’s claim rules, so a company seeking a local tax refund had to move through the city’s internal review, then an internal appeal, and only then file the formal claim that opens the courthouse door. Then the California Supreme Court flattened that detour.
The decision is Tesoro Refining & Marketing Company LLC v. City of Carson (Cal. Supreme Ct., Aug. 10, 2026), and it reaches every business paying a local tax in a city with its own refund ordinance. Chief Justice Guerrero, writing for a unanimous Court, held that the Government Claims Act preempts these local procedures.
How Carson’s Local Tax Refund Detour Worked
Carson voters approved an Oil Industry Business License Tax in 2017, charging refinery and petroleum storage operators a quarterly tax of one-quarter of one percent of their gross receipts from business in the city. Tesoro runs a refinery there. After an audit, Carson decided Tesoro had underpaid for a stretch spanning late 2017 into 2018 and sent a deficiency notice. Tesoro paid under protest, then filed a refund claim with the city clerk on the standard state form, arguing the assessment was untimely and the city’s calculation method was wrong. The city denied it, and Tesoro sued.
Carson’s response was procedural. It argued Tesoro had skipped steps, because the city’s ordinance says a taxpayer must first ask the finance director for a refund, then appeal to the city manager, before going to court. The trial court agreed and dismissed, and so did the Court of Appeal. But the Supreme Court reversed.
One Statewide Rulebook for Claims Against Local Government
The Government Claims Act sets a single, uniform procedure for presenting “all claims for money or damages against local public entities.” It spells out who files, what the claim must say, which form to use, where it goes, and how long the government has to respond, generally 45 days before the claim is deemed rejected and the claimant can sue. The Legislature built that system in the late 1950s and early 1960s to replace a chaotic patchwork of local rules the courts had long called “traps for the unwary.”
The legal engine of the decision is field preemption, the rule that when the Legislature means a statute to occupy an entire subject, a local law regulating in that same area cannot be enforced. Reading the Act’s text, structure, and history, the Court concluded the Legislature occupied the whole field of claim presentation. A city may write its own procedures only for the narrow categories the Act carves out, and local tax refunds are not among them.
A Refund Request Is a Claim, Whatever the City Calls It
Carson’s main move was to relabel its refund process as a separate administrative remedy the taxpayer had to exhaust first. The Court rejected the relabeling. A claim for money or damages is a demand asserting a right to be paid, and a request to recover an allegedly unlawful tax is exactly that. Because the city was imposing extra presentation steps on a claim the Act already governs, those steps fell. And once a procedure is preempted, there’s nothing left to exhaust.
One limit matters. The ruling covers local taxes set by a city’s own ordinance. It doesn’t touch property taxes, sales and use taxes, or other taxes whose refund procedures come from the Revenue and Taxation Code or another state statute.
What This Means for Businesses and Property Owners
If your company pays a local business or gross receipts tax and you think the city miscalculated it or assessed it too late, you no longer have to complete the city’s internal refund-and-appeal process before suing. Pay under protest if you must, file your claim under the state Act, and if the city denies it or misses its deadline, you can go to court. The city can’t add steps, add delay, or set a trap that forfeits your claim over one of its internal deadlines. That’s true even in charter cities, which often assume home rule lets them design their tax machinery end to end. It doesn’t reach how a refund claim gets presented.
The Bottom Line
Tesoro is a win for predictability. Businesses challenging a local tax now follow one clear procedure instead of a city-specific maze. If you’re weighing whether to contest a municipal assessment, the path to court is shorter and surer than the ordinance might suggest, and any local rule demanding extra pre-suit steps for a refund is now vulnerable. Tax disputes with local government, and the strategy around preserving and pursuing a refund, are work Horst Legal Counsel handles for business clients. If a city has assessed your business a tax you believe is wrong, we’re glad to talk it through. Contact us here.