California Code, Education Code - EDC § 76370

(a) If a fee for auditing is charged, it shall not exceed fifteen dollars ($15) per unit per semester.

The governing board shall proportionately adjust the amount of the fee for term lengths based upon a quarter system or other alternative system approved pursuant to regulations of the board of governors, and shall also proportionately adjust the amount of the fee for summer sessions, intersessions, and other short-term courses.  In making these adjustments, the governing board may round the per unit fee and the per term or per session fee to the nearest dollar.

(b) Students enrolled in classes to receive credit for 10 or more semester credit units shall not be charged a fee to audit three or fewer semester units per semester.

(c) No student auditing a course shall be permitted to change his or her enrollment in that course to receive credit for the course.

(d) Priority in class enrollment shall be given to students desiring to take the course for credit towards a degree or certificate.

(e) Classroom attendance of students auditing a course shall not be included in computing the apportionment due a community college district.