9.—(1) Subject to paragraph (2), in each year a water authority shall take, or cause to be taken–
(a)from its sampling points; or
(b)to the extent authorised by or under regulation 8, from its supply points,
the standard number of samples for analysis as regards residual disinfectant and each parameter listed in column (1) of Table 2 in Schedule 3 or, as the case may be, Tables 3 or 4 in that Schedule.
(2) Where, in respect of a parameter subject to check monitoring–
(a)a water authority is of the opinion that the quality of water supplied by it to a water supply zone is unlikely to deteriorate; and
(b)in each of two successive years the results of samples taken, subject to paragraph (3), in accordance with these Regulations show no significant variation and–
(i)if the parameter is colony counts, have shown no abnormal change;
(ii)if the parameter in question is hydrogen ion concentration (item 9 in Table 1 in Schedule 3), have established a pH value that is not less than 6.5 and not more than 9.5;
(iii)in any other case, have established a concentration or value for that parameter that is significantly lower than the prescribed concentration or value, or specification,
the number of samples to be taken in the following year for that parameter may be the reduced number.
(3) Where the following year is 2004, paragraph (2)(b) shall apply as if for “these Regulations" there were substituted “ the 1990 Regulations ”; and where the following year is 2005, paragraph (2)(b) shall apply as if before “these Regulations" there were inserted “ the 1990 Regulations and ”.
(4) Samples required to be taken by this regulation shall be taken at regular intervals.
(5) In this regulation–
(a)in relation to water supply zones, residual disinfectant or a parameter and the supply of water to an estimated population within one of the ranges shown in column (2) of Table 2 in Schedule 3, “the reduced number" and the “standard number" mean the number shown in column (3) and column (4), respectively, of that Table as applicable to that substance or parameter by reference to a population within that range; and
(b)in relation to supply points, each of the parameters specified in Table 3 of Schedule 3, and the supply of a volume of water within one of the ranges shown in column (3) of that Table, “the reduced number" and “the standard number" mean the number shown in column (4) and column (5), respectively, of that Table as applicable to that parameter by reference to a volume supplied within that range.