Short answer: Yes. Costco diesel is high-quality ultra-low sulfur diesel (ULSD) that meets or exceeds all federal and state fuel standards in the United States and Canada. If you've been wondering whether it's safe to fill up your truck, RV, or fleet vehicle at Costco, the answer is an emphatic yes.
All diesel fuel sold in the United States must meet ASTM D975 standards set by the American Society for Testing and Materials. This is the same standard that Shell, Chevron, BP, and every other major brand must meet. The EPA also mandates that all on-road diesel be ultra-low sulfur diesel (ULSD), meaning it contains no more than 15 parts per million (ppm) of sulfur.
Costco diesel meets both of these requirements. There is no "cheap grade" diesel that bypasses these standards — every drop of on-road diesel sold in America, whether at Costco or a premium-brand station, must comply.
Costco treats its fuel with additive packages designed to clean fuel injectors, prevent deposits, and improve engine performance. While Costco doesn't publish the exact formulation (no fuel retailer does), their gasoline is known to include deposit control additives that meet Top Tier standards — a voluntary standard exceeding EPA minimums.
For diesel, the key additive categories are:
Even if you want extra protection, adding a high-quality diesel fuel additive like Hot Shot's Secret Diesel Extreme at every fill-up can provide additional lubricity and cleaning beyond what any station's base additive package offers.
Here's the thing that surprises many drivers: diesel fuel is a commodity. In most markets, the base fuel sold at Costco comes from the same refineries and pipelines that supply Shell, Chevron, and BP stations. The difference is the additive package — and even then, all on-road diesel must meet the same minimum federal standards.
In practice, the diesel you buy at Costco is functionally equivalent to what you'd buy at any major-brand station. The big difference is price: Costco diesel is typically 10-30 cents per gallon cheaper than competing stations in the same market.
Modern diesel engines — including those in Ford Super Duty, Chevrolet Silverado HD, Ram HD, and diesel RVs — are designed to run on ULSD that meets ASTM D975. Costco diesel meets both requirements. If your vehicle has a diesel particulate filter (DPF) or selective catalytic reduction (SCR) system, Costco diesel won't cause any issues.
The only exception: if your vehicle requires biodiesel blends above B5, check your owner's manual. Costco does not typically sell biodiesel blends, so you'd need to find a station that specifically offers B20 or higher.
Renewable diesel (also called HVO or HDRD) is chemically identical to petroleum diesel and meets the same ASTM D975 standard. Some Costco locations in California and the Pacific Northwest may dispense renewable diesel blends, which are functionally identical to traditional ULSD from an engine compatibility standpoint. Renewable diesel actually burns cleaner than petroleum diesel.
Costco diesel is good quality, meets all regulatory standards, and comes from the same supply chain as name-brand stations. You're not sacrificing quality for the lower price — you're just buying a commodity product from a high-volume, low-margin retailer. Fill up with confidence.
Use our interactive Costco fuel map to find the nearest Costco diesel station. Filter for diesel-only locations, search by ZIP code, and get driving directions. We track 71 diesel locations across the US and Canada.
Popular diesel states: California (15), Washington (11), Texas (5), Utah (5).