Cal. PUC § 30740.5

The board of directors or any officer or member or members thereof authorized by that body, or any individual voter or bona fide association, or any combination of voters and associations, may file a written argument for or against any district bond or tax measure. No argument shall exceed 300 words in length. The county elections official of the County of Los Angeles shall cause an argument for and an argument against the measure to be printed, and shall enclose a copy of both arguments printed on the same sheet of paper in an envelope with each sample ballot. The printed arguments are official matter within the meaning of those words as used in Section 13303 of the Elections Code. Based on the time reasonably necessary to prepare and print the arguments and sample ballots for that election, the elections official shall fix and determine a reasonable date prior to the election after which no argument for or against the measure may be submitted to him or her for printing and distribution to the voters, as provided in this section. Arguments may be changed until and including the date fixed by the elections official. If more than one argument for or more than one argument against any measure is submitted to the elections official within the time prescribed, the elections official shall select one of the arguments in favor and one of the arguments against the measure for printing and distribution to the voters. The arguments so selected shall be those of bona fide supporters or opponents of the measure.