Motor Vehicle Safety Regulations

5.2 The gross vehicle weight rating of a vehicle shall be not less than the sum of

• (a) the unloaded vehicle mass,

• (b) the cargo-carrying capacity,

• (c) the product obtained by multiplying the designated seating capacity by 54 kg, in the case of a school bus, or by 68 kg, in any other case, and

• (d) in the case of a vehicle having living or sanitary accommodations, the mass of its fresh water, hot water and propane tanks, but not its waste water tanks, when full.