Investigations: indicator parameters
19.—(1) Where a water undertaker or supplementary licensee has reason to believe that water of a relevant description 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)whether water of a relevant description does or does not meet the specifications;
(b)the indicator parameters in respect of which the specifications are not met;
(c)if the specification for the coliform bacteria or colony counts 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;
(d)if the specification for the tritium parameter is not met, whether the inability to meet the specification is attributable to artificial radionuclides.
(2) As soon as possible after the matters specified in paragraph (1) have been identified, the water undertaker or supplementary licensee must—
(a)notify the Welsh Ministers—
(i)of those matters;
(ii)whether it is its opinion that, in relation to each parameter identified in accordance with paragraph (1)(b), a recurrence of the inability to meet the specification in respect of that parameter is likely; and
(b)send a copy of that notice to any other relevant supplier which uses the supply system for the purposes of supplying water to consumers who are likely to be affected by the failure.
(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 or supplementary licensee must, at the same time as notification is given under paragraph (2)—
(a)by notice in writing—
(i)to those of its consumers who are likely to be affected by the failure; and
(ii)to any other relevant supplier which uses the supply system for the purposes of supplying water to consumers who are likely to be affected by the failure, inform them of the nature of the failure and provide details of the steps (if any) that, in its opinion, 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 Welsh Ministers and to each appropriate local authority.
(4) A relevant supplier which receives a notice under paragraph (3)(a)(ii) must immediately send or cause to be sent a copy of that notice to those of its consumers who are likely to be affected by the failure.