17.—(1) Subject to paragraph (3), where a monitoring local authority considers a Type A supply fails, or is likely to fail, to satisfy a requirement of regulation 7(2) that authority shall immediately take such steps as are considered necessary to identify the following matters—
(a)the cause and extent of the failure, or as the case may be, the apprehended failure;
(b)the microbiological and chemical parameters listed in Tables A and B in Schedule 1 in respect of which the prescribed concentration or value has not been, or is unlikely to be, achieved; and
(c)in relation to each parameter so identified, whether the failure, or apprehended failure, to achieve the prescribed concentration or value is attributable to—
(i)the domestic distribution system;
(ii)the maintenance of that system; or
(iii)neither of those matters.
(2) Where a departure has been authorised under Part V—
(a)paragraph (1) shall apply only in respect of the microbiological and chemical parameters listed in Tables A and B in Schedule 1 (if any) that are not specified in the authorisation; and
(b)a monitoring local authority which has reason to believe that the Type A supply fails, or is likely to fail, to satisfy the concentration or value required by the authorisation in relation to any of those, it shall immediately take such steps as are necessary to identify the matters specified in paragraph (1).
(3) As soon as reasonably practicable after the matters specified in paragraph (1) have been identified, the monitoring local authority shall notify the relevant person and the appropriate local authority—
(a)of those matters; and
(b)in relation to each parameter identified in accordance with paragraph (1)(b) whether the monitoring local authority considers a failure in respect of the parameter is likely to recur;
(c)of the action (if any) taken by that authority in relation to a failure which is attributable to the domestic distribution system or the maintenance of that system; and
(d)details of the steps (if any) that the authority considers it is necessary or desirable for consumers of the supply likely to be affected by the matters specified in paragraph (1) to take in the interests of their health.
(4) As soon as reasonably practicable after the relevant person receives notification given under paragraph (3), that person shall notify, in writing—
(a)every consumer of that supply; and
(b)where directed to do so by the monitoring local authority, every consumer the relevant person reasonably believes may have been or was likely to have been affected by the matters specified in paragraph (1), where the address or contact details of those consumers are known to that person or are readily ascertainable,
of the matters referred to in paragraph (3)(a) to (d).
(5) Where the monitoring local authority has identified a failure which is attributable to a domestic distribution system or the maintenance of that system, it shall, at the same time as notice is given under paragraph (3)—
(a)notify in writing the responsible person in relation to that domestic distribution system, and having consulted with the health board in whose area the supply is located, inform that person of the nature of the failure and provide details of the steps (if any) that the authority considers it is necessary or desirable for that person and any other consumers of that supply to take in the interests of their health; and
(b)send a copy of the notification under sub-paragraph (a) to the relevant person in relation to the private water supply.
(6) Where the monitoring local authority considers such a failure as is mentioned in paragraph (5) is likely to affect the supply of water to the public in premises in which water is so supplied, the authority shall at the same time as notice is given under paragraph (5)—
(a)by notice in writing to the responsible person in respect of that domestic distribution system, inform that person of the nature of the failure and provide details of the steps (if any) that the authority considers it is necessary or desirable for that person and any other consumers of that supply to take in the interests of their health; and
(b)send a copy of that notice to the relevant person in relation to the private water supply.
(7) As soon as reasonably practicable after a responsible person receives a notification given under paragraph (6)(a), that person shall—
(a)where directed to do so by the monitoring local authority, serve a copy of that notice on every consumer the responsible person reasonably believes may have been or was likely to have been affected by the failure, where the address or contact details of those consumers are known to that person or are readily ascertainable;
(b)prominently display a copy of the notice given under paragraph (6)(a) so that it might be conveniently read by any consumer that may attend at the premises; and
(c)take all such other steps as the monitoring local authority may reasonably require to inform the public of the failure.
(8) Where such a failure as is mentioned in sub-paragraphs (a) to (c) of paragraph (1) relates to the copper or lead parameter, the monitoring local authority shall, as soon as reasonably practicable after the occurrence, advise the responsible person to modify or replace such of the pipes and their associated fittings as it knows or has reason to believe have the potential for contributing to copper or lead in the water supplied to the premises served by that supply, so as to eliminate that potential (whether or not the presence of copper or lead in those pipes contributed to the failure).