Cal. Rev. & Tax. Code § 203

(a) The college exemption is as specified in subdivision (e) of Section 3 and Section 5 of Article XIII of the California Constitution.
(b) An educational institution of collegiate grade is an institution incorporated as a college or seminary of learning that requires for regular admission the completion of a four-year high school course or its equivalent, and confers upon its graduates at least one academic or professional degree, based on a course of at least one year in flight test technology or flight test science, for which the master’s degree program has been approved by the California Council for Private Postsecondary and Vocational Education or the Bureau for Private Postsecondary and Vocational Education, on a course of at least two years in liberal arts and sciences, or on a course of at least three years in professional studies, such as law, theology, education, medicine, dentistry, engineering, veterinary medicine, pharmacy, architecture, fine arts, commerce, or journalism.
(c) An educational institution of collegiate grade is not conducted for profit when it is conducted exclusively for scientific or educational purposes and no part of its net income inures to the benefit of any private person.
(d) Without prejudice to the right to assert an exemption otherwise available under subdivision (a), (d), or (e) of Section 3 of Article XIII of the Constitution, a property tax under this division shall be imposed upon that portion of the bookstore property determined to be generating the unrelated business taxable income, as defined in Section 512 of the Internal Revenue Code, to the extent property is both of the following:
1. (1) Owned by an educational institution of collegiate grade or used by a nonprofit corporation operating a student bookstore affiliated with an educational institution of collegiate grade.
2. (2) Primarily devoted to bookstore use that produces income that is taxable as unrelated business taxable income.
  This tax shall be determined by establishing a ratio of the unrelated business taxable income to the bookstore’s gross income as defined by the Internal Revenue Code. That percent shall be the maximum percentage of the bookstore property on which a property tax can be levied.
  At the end of a fiscal year when unrelated business income has been generated, the nonprofit organization shall file with the assessor copies of the organization’s most recent tax return filed with the Internal Revenue Service.