A proposed zone shall contain at least 12 voters, as defined in Section 359 of the Elections Code. However, where there are fewer than 12 registered voters within a proposed zone, the public agency may form a zone if the county health officer determines that an existing or potential public health hazard exists. The board of supervisors shall receive a notice of this determination.
Source:
Section 6955.1, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=HSC§ionNum=6955.1..