Cal. Wat. Code § 52179
In the event the bonds are callable at a premium, the board shall draw a warrant or warrants in favor of the county treasurer from time to time as bonds are called for redemption in an amount equal to the amount of the premium required to be paid on the bonds then called for redemption. Each such warrant shall be drawn against funds derived from the additional or supplemental assessment required to be levied pursuant to Section 51301.5. The amounts collected on such additional or supplemental assessment shall be used by the county treasurer for the payment of the premium on the bonds then called for redemption and, to the extent of such payment, such warrant shall be reduced or canceled by endorsement on the reverse thereof.
Ca. Water Code § 52179