Cal. Health & Safety Code § 4972

A copy of the resolution headed “Notice of Sewer Work,” in letters not less than one inch in height, shall be posted in the district along the entire length of that street in the district which, in the opinion of the governing body, is traversed by the largest number of people. The notices shall be posted not less than 300 feet in distance apart, and not less than three notices shall be posted in any case.