California Code, Health and Safety Code - HSC § 19835

(a) A deposit, either with the local agency or a responsible escrow agent or trust company, at the option of the local agency, of money or negotiable bonds of the kind approved for securing deposits of public moneys.

(b) An instrument of credit from one or more financial institutions subject to regulation by the state or federal government and pledging that the funds necessary to carry out the act or agreement are on deposit and guaranteed for payment or a letter of credit issued by such a financial institution.

(c) Bond or bonds by one or more duly authorized corporate sureties.

(d) Any form of security which is acceptable to the local agency and specified by ordinance thereof.