Cal. Educ. Code § 17420

All bonds, notes, warrants or other evidences of indebtedness referred to in Section 17419 and the interest thereon, and all bonds, notes, warrants, or other evidences of indebtedness issued to refinance any bonds, notes, warrants, or other evidences of indebtedness referred to in Section 17419 and the interest thereon, are exempt from all taxation in the state other than inheritance, gift and franchise taxes.