The license fee imposed by this part does not apply to any vehicle owned by an educational institution of collegiate grade, not conducted for profit, having an enrollment of 5,000 students or more and having an acreage of 5,000 acres or more, if such vehicle is used for fire-fighting purposes within the limits of the acreage of such institution, and is operated principally on roads owned by such institution.
Ca. Rev. and Tax. Code § 10786