Cal. Water Code § 25800.2

In the event the annual assessment for any parcel of land separately assessed, computed pursuant to Sections 25800 and 25801, is less than ten dollars ($10), a minimum annual assessment may be set by the board which shall not exceed ten dollars ($10) for each such separately assessed parcel of land, and upon a determination by the board that a minimum assessment shall be set, the secretary shall enter that assessment for each separately assessed parcel of land for which the annual assessment is less than the amount set by the board.