Subject to the provisions of this Part, the expenditure incurred by a council of a region or islands area in meeting any requisition under Part IV or VIII and in the exercise of any of their functions under any enactment in relation to water supply in their region or area shall, in so far as not otherwise met, be defrayed as to such portion thereof as may be determined under section 44 out of the regional rate or the general rate, as the case may be, and as to the remainder out of a rate to be levied as hereafter in this Act provided.

The portion of the regional rate or of the general rate levied under the foregoing subsection is hereafter in this Act referred to as " the public water rate ".

For the purpose of defraying the remainder of the expenditure mentioned in subsection (1), the council of a region or islands area shall, subject to the provisions of this Part, levy annually within their region or area a rate (hereafter in this Act referred to as " the domestic water rate ") which, notwithstanding anything in any other enactment, shall be levied as a separate rate.