California Code, Public Utilities Code - PUC § 29172

Registered bonds may be issued without limitation as to principal amount, as may be determined by the district, except that registered bonds shall be in denominations of one thousand dollars ($1,000) or multiples thereof.  Registered bonds of any denomination shall be exchangeable with bonds, either in registered or coupon form, of other denominations on such terms and conditions as the district shall determine, including provisions for authentication of bonds issued upon such exchange by the registration agent or other agents appointed by the district for that purpose, and upon the payment of such reasonable charges as may be prescribed by the district.