Cal. Health and Safety Code § 4611

On the day fixed for the hearing, or any day to which the hearing is continued, the governing body shall hear and consider all written and oral objections presented to the formation of the district, the inclusion of any lands in the district, or the making of the improvement which is proposed. At the hearing, the governing body may make changes in the improvement but the estimated costs and expenses of the improvement as changed, as determined by the governing body at the time of the change, shall not exceed by more than 10 percent the amount determined under Section 4607. At the hearing, the governing body may exclude from the district any territory that in its opinion would not be benefited by the improvement as finally determined. The governing body shall not, however, modify the boundaries of the proposed district so as to exclude from it any land which would in the judgment of the governing body be benefited by the improvement as finally determined nor shall the governing body include in the proposed district any lands which will not in its judgment be so benefited.