(1) Insert the following heading to section 164 of the Principal Act—
" Exercise of functions of Authority outside its water supply district ".
(2) For section 164(2) of the Principal Act substitute —
"(2) An Authority must not provide a service under this Part outside its water supply district unless—
(a) the service is capable of being conveniently provided by the use of resources that are not immediately required in carrying out the Authority's functions under this Act; and
(b) if the service relates to land in another Authority's water supply district, that Authority has agreed to the service being provided.".