Cal. Health & Safety Code § 25270.4.5
(b) A tank facility located on and operated by a farm, nursery, logging site, or construction site is not subject to subdivision (a) if no storage tank at the location exceeds 20,000 gallons of petroleum and the cumulative petroleum storage capacity of the tank facility does not exceed 100,000 gallons. Unless excluded from the definition of an “aboveground storage tank” in Section 25270.2, the owner or operator of a tank facility exempt pursuant to this subdivision shall take the following actions: