1. The State Excise Tax: 68.1¢/Gallon
California's base state excise tax is 68.1¢/gallon— second highest in the nation behind Pennsylvania (77.9¢). The federal tax adds another 18.4¢. Combined, that's 86.5¢ before you add any of California's other unique costs.
The national average for combined state + federal gas taxes is about 51¢. California's 86.5¢ base is already 35¢ above average — and that's just the starting point.
2. Cap-and-Trade: +15–25¢/Gallon
California runs the largest carbon cap-and-trade market in North America under AB 32 (the Global Warming Solutions Act). Fuel distributors must buy carbon allowances for every metric ton of CO₂ equivalent their product will produce when burned.
In practice, they pass this cost to consumers. When carbon allowance prices are high (they've been around $35–40/metric ton), the gas price impact is roughly 15–25¢/gallon. This number fluctuates quarterly with allowance auction prices.
This is arguably the most defensible cost on the list — it's designed to make carbon emissions more expensive, which reduces consumption and funds clean energy programs. But it unquestionably adds to your fill-up.
3. The Low Carbon Fuel Standard (LCFS): +40–65¢/Gallon
This is the biggest driver of California's gas price premium in recent years — and the least understood.
The LCFS requires fuel producers to progressively lower the "carbon intensity" of their fuel mix. Refiners who sell conventional gasoline (which is high-carbon) must purchase LCFS credits from producers of low-carbon fuels (EV charging, hydrogen, biodiesel, ethanol).
LCFS credit prices collapsed in 2024 as the credit market oversupplied, then rebounded. At peak, LCFS added over 65¢/gallon to California gas prices. The California Air Resources Board (CARB) proposed regulatory changes in 2024 to tighten the standard and prevent another crash — which could push prices higher through 2030.
Combined with cap-and-trade, California's two carbon programs alone add 60–90¢ per gallon that consumers in other states simply don't pay.
4. The "California Blend" (CARB Gasoline): +10–20¢
California requires its own unique gasoline formulation — sometimes called "CARB gas" or "California blend." It has tighter emissions standards than the EPA's national "reformulated gasoline" requirements and is designed to reduce smog in the state's notoriously bad-air basins (Los Angeles, Central Valley).
The problem: no other state uses this formula. It can only be produced by California-approved refineries. That means when a California refinery goes down for maintenance or after a fire (Valero, Chevron Richmond, and others have had major incidents), the state can't import replacement supply from the rest of the US. It has to source from Asia or wait for California refineries to come back online.
This "reformulation penalty" adds 10–20¢ in normal times. During refinery disruptions it can spike prices by $0.50–1.00/gallon literally overnight — which is why California gas stations sometimes show prices that seem disconnected from national trends.
5. Refinery Isolation: +5–15¢
The continental US has an extensive network of refined product pipelines. When supply is tight in the Midwest, refineries can ship product from the Gulf Coast. The East Coast is served by the Colonial Pipeline. Supply can generally move to where it's needed.
California doesn't connect to this network. No major pipeline brings refined gasoline into the state from outside. The state is essentially an island for fuel supply — served only by its own refineries and marine imports.
This isolation means California pays a structural premiumfor supply flexibility. When California demand spikes (summer driving, refinery outage), prices respond sharply because there's no national pipeline to draw on.
6. Underground Storage Tank Fee: +2¢
Small but fixed: a 2¢/gallon environmental fee to fund cleanup of leaking underground storage tanks. California has thousands of them, and remediation is expensive. This one is at least easy to explain.
The "Mystery Surcharge" — What Nobody Can Explain
In 2015, the California Energy Commission released a study showing California drivers were paying about 10¢/gallon more than even all the above costs could account for. They called it an "unexplained premium."
The leading theories: California's concentrated refinery market (a handful of companies control almost all production) allows for coordinated pricing behavior. When a refinery goes offline, competitors are slow to discount their spare capacity — they benefit from the tighter supply. It's not illegal collusion, but it's not competitive pricing either.
In 2024, Governor Newsom signed legislation creating a new state oversight board with authority to penalize refiners for excessive margins. The oil industry called it a de facto windfall profit tax. Whether it reduces the mystery surcharge remains to be seen.
Is It Worth Driving Across State Lines?
If you live near Nevada or Arizona, the math can actually work. Gas in Nevada and Arizona typically runs $0.60–1.00/gallon cheaper than California.
On a 15-gallon fill-up at $0.80 savings/gallon = $12 saved. If the detour is under 15 miles round trip, you break even or come out ahead (assuming ~30 MPG, $4/gal CA gas, the detour costs you about 0.5 gallons = $2). For a 20-gallon SUV tank, the savings are even more compelling.
Gas stations just inside Nevada on I-15 (near Primm) and I-80 (near Reno) are known specifically for California cross-border traffic. Some stations near the Arizona border on I-8 and I-40 similarly price aggressively knowing they're getting California commuters.
Will California Gas Prices Ever Come Down?
Not structurally. The LCFS standard gets tighter every year through 2030 by design — that's the policy intent, to push consumers toward EVs by making gasoline progressively more expensive relative to electricity. Cap-and-trade allowance prices are scheduled to rise over time. The state excise tax is inflation-indexed.
The cost gap between California and the rest of the US is a feature, not a bug, from the perspective of state climate policy. It's also why California has the highest EV adoption rate in the country — the financial incentive to switch is largest here.
Track today's California prices vs. the national average on our California gas prices page.