Cal. Water Code § 75370

The board of supervisors of each affected county shall, annually, at the time of levying county taxes, levy an assessment tax to be known as the “____ (name of district) water conservation district assessment,” sufficient to raise the amount (except the amount required to pay principal and interest of bonds) reported to it by the board, and shall also levy an assessment tax to be known as the “____ (name of district) water conservation district bond fund assessment,” sufficient to raise the amount for bond service reported to it by the board.