Health & Saf. Code, § 4764

It may borrow money and incur indebtedness and guarantee the performance of its legal or contractual obligations whether heretofore or hereafter incurred; and also refund or retire any public indebtedness or lien that may exist against the district or any property therein which shall have arisen out of the transaction of the affairs of the district. It shall not, however, incur any bonded indebtedness unless it submits the proposition for incurring the bonded indebtedness to the voters of the district, or if the bonded indebtedness is for an improvement district, to the voters of the improvement district, at a regular election or a special election called for that purpose and at least two-thirds of the votes cast at the election are in favor of incurring the bonded indebtedness as proposed.