Cal. Pub. Util. Code § 16075

No ordinance passed by the board takes effect less than 30 days after its passage. At least one week before the expiration of the said 30 days copies of the ordinance shall be posted by the clerk at three public places in the district, and if there is a newspaper of general circulation printed and published in the district, the ordinance shall be published in the newspaper pursuant to Section 6061 of the Government Code.