20.— (1) The functions of each water services authority under paragraph (f) of subsection (1) of section 32 of the Act of 2007 shall, in addition to being performable by a water services authority, be performable by F41[the metering authority] in so far only as they relate to premises that contain one or more dwellings, and references in any enactment or instrument under an enactment to a water services authority shall, to the extent that they relate to any such function, be construed as including references to F41[the metering authority].

(2) For the purposes of this Part and subject to subsection (3), the functions (other than the functions referred to in subsection (1)) of a water services authority under the Act of 2007 shall, in addition to being performable by a water services authority, be performable by F41[the metering authority]—

(a) in the like manner as they would be performable by a water services authority,

(b) subject to the like consent and conditions (if any) as would apply if the functions were being performed by a water services authority, and

(c) to the extent only that their performance is necessary or expedient for the performance of functions referred to in subsection (1).

(3) For the avoidance of doubt, the functions to which this section applies shall be performable by—

F42[(a) a water services authority, or

(b) the metering authority.]

(c) F43[…]