Cal. Education Code § 17040.9

(a) (1) The board shall allocate the amount calculated under subdivision (b), in addition to any other project funding authorized under this chapter, to each project funded under this chapter for which the resulting pupil density will exceed the following: (A) For a project for kindergarten or any of the grades 1 to 6, inclusive, 90 pupils per acre. (B) For a project for a junior high school project, 80 pupils per acre. (C) For a project for a senior high school project, 70 pupils per acre. (2) For any new construction project, pupil density shall be computed, for purposes of paragraph (1), by dividing the number of units of estimated average daily attendance for the project, including those to be served by relocatable structures, by the acreage of the project site. (3) For any project for the construction of additional facility space on an existing schoolsite or on land acquired that is adjacent to an existing schoolsite, pupil density shall be computed, for purposes of paragraph (1), by adding the number of units of estimated average daily attendance for the project to the number of units of average daily attendance for the existing school facilities, and dividing that sum by the total site acreage for the project and the existing school facilities. (b) The supplemental project funding authorized under this section shall be calculated by dividing the actual pupil density for the project, as calculated under subdivision (a), by the threshold pupil density for the project as set forth in that subdivision, and multiplying the resulting fraction by an amount equal to the average cost per acre of the land approved for acquisition by the board under this chapter for the project, or that would have been approved for acquisition if the applicant school district had not had an existing schoolsite available for the project.