Where to buy off-road (dyed) diesel

What off-road diesel is

Since 2010 every gallon of diesel sold in the U.S. for on-road or off-road engines has had to be ultra-low-sulfur (15 ppm), so dyed diesel is the same ULSD fuel as pump diesel. The only differences are a red dye (Solvent Red 164, at a concentration the IRS specifies) and the taxes. The federal excise tax on highway diesel is 24.4¢ per gallon; dyed fuel is sold without it, and most states also waive some or all of their own fuel tax for off-highway use. The dye is there so a roadside inspector can tell at a glance whether the tank was filled with taxed fuel.

Other names for the same thing: red diesel, farm diesel, dyed ULSD, nontaxed diesel, No. 2 off-road. Home heating oil is also dyed red and is chemically a close cousin, but it is sold under a different spec and often with a higher sulfur limit; don’t put it in a Tier 4 engine.

Who is allowed to use it

Federal law (26 U.S.C. §4082) lets dyed diesel be sold tax-free for “nontaxable uses,” which in practice means engines that never touch a public road:

• Farm tractors, combines, irrigation pumps and other equipment used on a farm for farming purposes.
• Construction and mining equipment: excavators, loaders, dozers, generators and light towers on a site.
• Stationary engines and standby generators, including home backup generators.
• Boats used in commercial fishing and other qualifying marine use, and some rail use.
• Home heating and other non-engine uses.

What it does not cover is any vehicle registered for highway use: pickups, dump trucks driven on the road, RVs, or a tractor that commutes between fields on a public road in a state that doesn’t exempt that. The penalty under 26 U.S.C. §6715 is the greater of $1,000 or $10 per gallon of dyed fuel involved, assessed per act, and it rises with each prior violation. Inspectors do dip tanks at weigh stations and construction sites. If you ever need to run dyed fuel in a road vehicle in an emergency (a declared fuel shortage, for example), the IRS issues a specific waiver and announces it; absent that, don’t.

Where to buy it

Cardlock networks

The biggest source for anyone who isn’t a farm. A cardlock is an unattended fuel island open 24 hours to card holders, and most carry a dyed diesel hose alongside clear diesel and DEF. The two national networks are CFN (Commercial Fueling Network) and Pacific Pride, each with a site locator on its website and an app, and each accessed through a local fuel distributor who issues the card and bills you monthly. Regional networks (Fuelman, WEX-accepting sites, co-op cardlocks like Cenex and FS) work the same way. The catch is that you need the account before you can fuel, and the locator doesn’t always say which hose is dyed, so ask the distributor when you sign up. For a small contractor, one cardlock account usually covers it.

Farm co-ops and fuel jobbers

If you have a tank, this is the cheapest way. Co-ops (CHS/Cenex, Growmark/FS, Southern States, the independents) and petroleum jobbers deliver dyed diesel by the tank wagon, and will usually rent or sell you a skid tank with a pump. Minimums vary by company and season; expect a few hundred gallons as the smallest routine drop, and ask about a seasonal contract if you burn a lot in spring and fall. The same truck can deliver B20 off-road blends in the Midwest or R99 off-road in California (see below).

Rural gas stations and farm-supply stores

In farm country a fair number of independent stations and ag retailers keep a dyed pump, often around the back or marked “farm diesel.” There is no directory of these; Yelp and the map apps are hit-and-miss because the listings are user-submitted. Asking at the local co-op or the implement dealer works better than searching. Big-box farm stores sell kerosene and packaged fuel but generally not dyed diesel from a pump.

What won’t work

Highway truck stops and brand-name gas stations sell clear, taxed diesel only. The DOE’s Alternative Fueling Station Locator, which powers the biodiesel map on this site, lists only alternative fuels at public retail sites; it doesn’t track dyed diesel, and neither does any federal database.

How it’s priced

Start from the posted price of clear diesel and subtract the taxes that don’t apply: the 24.4¢ federal excise, plus whatever share of the state fuel tax your state waives for off-highway use (most of it in most states; check your state’s department of revenue, because a few collect sales tax instead). That puts dyed diesel typically 30–70 cents a gallon under pump diesel, depending on the state. Delivered bulk pricing adds a delivery charge and depends on volume; cardlock pricing is usually a little above bulk and a little below retail.

Prices move with the same crude and distillate markets as road diesel. The “off-road diesel prices near me” pages you’ll find online are mostly individual jobbers posting their own daily rack-plus price, which is a fine way to get a quote but not a market average.

Biodiesel and renewable diesel off-road

Off-road fuel can be any diesel, and in two regions it often isn’t straight petroleum. In Iowa, Minnesota and Illinois, co-ops routinely deliver dyed B5 to B20 to farms, both because the state incentives apply to off-road gallons and because the engine makers approve it: John Deere, Case IH and New Holland all allow B20 in current equipment, and several allow higher blends in older engines. In California, fleets and construction companies burn dyed R99 because the Low Carbon Fuel Standard makes it competitive with petroleum. The engine rules are the same as on-road: biodiesel counts against your manufacturer’s blend limit, renewable diesel doesn’t. Our guides on approved biodiesel blends and renewable diesel vs biodiesel cover the details, and the renewable diesel locator shows retail R99.

One off-road-specific caution: equipment that sits for months should be stored on straight diesel or B5, not B20, because biodiesel oxidizes and absorbs water in a half-full tank. R99 stores as well as diesel.

Buying tips

1. Keep the paperwork. A delivery ticket or cardlock statement showing dyed fuel bought for a farm or job site is what you show an inspector if a question ever comes up.
2. Separate tanks, labeled. If you have both clear and dyed fuel on site, label the tanks and the cans. Cross-contamination into a road vehicle is the most common way honest operators get penalized.
3. Ask for winter fuel. Bulk dyed diesel is often summer-grade No. 2; if your tank sits outside, ask for a winter blend or add anti-gel before the first freeze.
4. Check the sulfur. Any dyed diesel sold today should be ULSD. If a seller can’t say, don’t put it in a Tier 4 engine with a particulate filter.
5. Compare per gallon delivered, not per gallon posted. Delivery fees and minimums change the math at small volumes; a cardlock may beat delivery below a few hundred gallons a month.

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