Treatment of raw water
26.—(1) In carrying out such of its functions under Chapter III as comprise the supply of water for regulation 4(1) purposes, a water undertaker shall not, subject to paragraph (2), supply water from any source which consists of or includes raw water unless the water has been disinfected and, in the case of surface water, subjected to at least such further treatment as is specified in paragraph (3).
(2) This paragraph shall not require a water undertaker to disinfect such groundwaters as are specified in an authorisation given by the Secretary of State for the purposes of this paragraph.
(3) The further treatment mentioned in paragraph (1) is such treatment as is required to secure compliance with Council Directive 75/440/EC (quality required of surface water intended for the abstraction of drinking water)(1); and for the purposes of this regulation, surface water shall be treated as falling within category A1 or A2 or A3 set out in Annex I to that Directive if it is abstracted from waters for which the classification to be currently satisfied in accordance with section 82(1) of the Water Resources Act 1991(2) is, as appropriate, DW1 or DW2 or DW3, as set out in the Surface Waters (Abstraction for Drinking Water) (Classification) Regulations 1996(3).
(4) Except with the consent of the Secretary of State, water shall not be abstracted for supply for domestic purposes which include drinking except from waters to be treated as falling within category A1 or A2 or A3 in the Annex mentioned in paragraph (3).