Cal. Educ. Code § 15125

The proceedings relating to the authorization of bonds of a joint school district of any type need be certified only to the board of supervisors of the county whose superintendent of schools has jurisdiction over the district. The board of supervisors may issue and sell the bonds and no action of the board of supervisors of any other county in which the district is situated shall be required in connection with the issuance and sale, and the bonds need not be signed by any officer of any the other county.