Cal. Water Code § 55525

The bonds shall be signed by the chairman of the board and countersigned by the auditor of the district, or if one has not been appointed, the auditor of the county and the seal of the district shall be affixed thereto. All such signatures and countersignatures, except one, may be printed, lithographed, engraved, or otherwise mechanically reproduced. Any such signature may be affixed in accordance with the provisions of the Uniform Facsimile Signatures of Public Officials Act, Chapter 6 (commencing with Section 5500) of Title 1 of the Government Code.