Cal. Water Code § 74572

If the district is annexed to a cooperating district, all bonds of the annexed district authorized for payment of its agreed share of the cost and expense of the construction and operation of works or the acquisition of property by the annexing cooperating district, shall be issued and shall be delivered to and received by the annexing district at not less than par value. Such bonds shall become the property of the annexing district and they may be collected at maturity or sold by the annexing district at not less than par value and the proceeds of sale applied to the purpose for which the bonds were issued.