If the charge for any parcel of land separately charged, based on the rate fixed pursuant to Section 75471, is less than ten dollars ($10), a minimum charge may be set by the board which shall not exceed ten dollars ($10) for each separately charged parcel.
Source:
Section 75471.5, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=WAT§ionNum=75471.5..