Cal. Elec. Code § 2250

On and after July 1, 2007, in any document mailed by a state agency that offers a person the opportunity to register to vote pursuant to the federal National Voter Registration Act of 1993 (52 U.S.C. Sec. 20501 et seq.) that state agency shall include a notice informing prospective voters that if they have not received voter registration information within 30 days of requesting it, they should contact their local elections office or the office of the Secretary of State.