Cal. Pub. Res. Code § 26561

Notice of the hearing set pursuant to Section 26557 or subdivision (c) of Section 26558 shall be mailed first-class, postage prepaid, in the United States mail, at least 20 days preceding the date of the public hearing, to each owner of real property within the proposed district as shown on the last equalized county assessment roll, or the State Board of Equalization assessment roll, as the case may be.