The following expenses of a rural authority, that is to say—
shall, so far as they fall to be defrayed out of rates, be special expenses chargeable on that contributory place, but without prejudice to the powers of the authority under subsection (4) of the said section one hundred and ninety.
For the purposes of paragraph (a) or paragraph (b) of the preceding subsection, contributions towards the expenses of a joint board shall be deemed to be expenses incurred by the contributing council.
Where a rural authority determine to defray as part of their general expenses the whole of any expenses which would otherwise be defrayed as special expenses chargeable upon a contributory place, or upon two or more contributory places, it shall not be necessary for the authority to keep parochial accounts in respect of those expenses and, if those expenses were incurred in respect of separate undertakings for supplying water, those undertakings shall for the purposes of this Act and of the Local Government Act. 1933. be deemed to be one undertaking.