Verdict: prohibited. Under Ontario law a farm-plated truck — a truck registered under the Highway Traffic Act with reduced-fee farm plates issued pursuant to R.R.O. 1990, Reg. 628 — is a "motor vehicle to which a number plate is attached as required under the Highway Traffic Act" within the meaning of Fuel Tax Act s. 2(7.1). It may not carry or run coloured (dyed) diesel under any operating condition, including on-farm-only operation, movement between contiguous farm parcels, or movement on a public highway.
The Ministry of Finance is explicit: "It is prohibited to use coloured fuel in a licensed motor vehicle, even if the motor vehicle is operated primarily in connection with a farming, construction, forestry, or mining business" (Ontario Tax Bulletin "Coloured Fuel"). The Ministry's "Attention Truckers" pamphlet reinforces this: "Dyed diesel must not be used to fuel a licensed motor vehicle, even if the motor vehicle is operated primarily in connection with the business of farming, construction, forestry or mining."
A farm plate is a reduced-fee commercial plate, not an exemption from licensing. The Ontario Federation of Agriculture confirms there is "NO exemption for farm-plated trucks" from licensed-vehicle rules; the same principle applies here — a farm plate is a Highway Traffic Act number plate.
Unlicensed farm equipment — tractors, combines, SPIH, grain dryers, irrigation pumps, on-farm gensets — may use coloured fuel because they are not motor vehicles required to be licensed under the HTA. Off-road vehicles plated only under the Off-Road Vehicles Act (no HTA number plate) may also use coloured fuel, per the MTO Farm Guide.
A licensed truck may use coloured fuel for auxiliary equipment only when the auxiliary equipment is fuelled from a separate fuel tank that is physically not connected to the truck's drive engine. Typical case: a refrigeration ("reefer") unit on a trailer that has its own dedicated diesel tank — that reefer tank may be filled with coloured fuel because the use is a non-taxable refrigeration use, not propulsion of the licensed vehicle. The same applies to certain power-take-off (PTO) auxiliary units with separate fuel supply.
The carve-out fails the moment the auxiliary equipment shares a tank with the truck's propulsion engine — even a single cross-feed line invalidates the exemption. The Ministry of Finance enforces this strictly: a dip test on the propulsion tank is the test that matters, and any dye there is the offence.
A farm with both a farm-plated pickup and a tractor must keep clear diesel for the pickup and coloured diesel for the tractor — typically in separate, labelled tanks. A trucker with a reefer trailer must keep the truck's drive tank clear and may keep the reefer's separate auxiliary tank coloured.
Confidence: verified (primary source confirmed 2026-05-13).
Verdict: prohibited. Under Ontario law a farm-plated truck — a truck registered under the Highway Traffic Act with reduced-fee farm plates issued pursuant to R.R.O. 1990, Reg. 628 — is a "motor vehicle to which a number plate is attached as required under the Highway Traffic Act" within the meaning of Fuel Tax Act s. 2(7.1). It may not carry or run coloured (dyed) diesel under any operating condition, including on-farm-only operation, movement between contiguous farm parcels, or movement on a public highway.
The Ministry of Finance is explicit: "It is prohibited to use coloured fuel in a licensed motor vehicle, even if the motor vehicle is operated primarily in connection with a farming, construction, forestry, or mining business" (Ontario Tax Bulletin "Coloured Fuel"). The Ministry's "Attention Truckers" pamphlet reinforces this: "Dyed diesel must not be used to fuel a licensed motor vehicle, even if the motor vehicle is operated primarily in connection with the business of farming, construction, forestry or mining."
A farm plate is a reduced-fee commercial plate, not an exemption from licensing. The Ontario Federation of Agriculture confirms there is "NO exemption for farm-plated trucks" from licensed-vehicle rules; the same principle applies here — a farm plate is a Highway Traffic Act number plate.
Unlicensed farm equipment — tractors, combines, SPIH, grain dryers, irrigation pumps, on-farm gensets — may use coloured fuel because they are not motor vehicles required to be licensed under the HTA. Off-road vehicles plated only under the Off-Road Vehicles Act (no HTA number plate) may also use coloured fuel, per the MTO Farm Guide.
A farm with both a farm-plated pickup and a tractor must keep clear diesel for the pickup and coloured diesel for the tractor — typically in separate, labelled tanks.
Confidence: verified (primary source confirmed 2026-05-13).