22.—(1) Where the water undertaker has reason to believe that water supplied by it for regulation 5(1) purposes does not meet the specifications for indicator parameters set out in Schedule 2, it must immediately take such steps as are necessary to identify—
(a)the reason why the specifications are not met;
(b)the indicator parameters in respect of which the specifications are not met; and
(c)if the specification for the coliform bacteria or colony count parameter (items 4 and 5 in Schedule 2) is not met, whether the inability to meet that specification is attributable—
(i)to the domestic distribution system;
(ii)to the maintenance of that system; or
(iii)to neither of those matters.
(2) Immediately after the matters specified in paragraph (1) have been identified, the water undertaker must notify the Department—
(a)of those matters; and
(b)in relation to each parameter identified in accordance with paragraph (1)(b), whether it is the opinion of the water undertaker that a recurrence of the inability to meet the specification in respect of that parameter is likely.
(3) Where, in a case to which paragraph (1)(c) applies, the inability to meet the specification has been identified as attributable to the domestic distribution system or to the maintenance of that system, the water undertaker must, at the same time as notification is given under paragraph (2)—
(a)by notice in writing to those of its consumers—
(i)to whom it supplies water for regulation 5(1) purposes; and
(ii)who are likely to be affected,
inform them of the nature of the failure and provide details of the steps (if any) that, in the opinion of the water undertaker, it is necessary or desirable for those consumers to take in the interests of their health; and
(b)send a copy of that notice to the Department and to each appropriate district council.