California Code, Public Utilities Code - PUC § 99336

The principal of and interest on the bonds and any premiums upon the redemption of any thereof are not a debt of the county, nor a legal or equitable pledge, charge, lien, or encumbrance upon any of its property, or upon any of its income, receipts, or revenues, except the revenues that may be legally applied, pledged, or otherwise made available to their payment.