Regulation 13 Frequency of sampling
Subject to paragraphs (2) to (9), in each year a water authority shall take from its sampling points, or, as the case may be, its supply points, for analysis for testing for compliance with each parameter not less than such standard number of samples as is specified in Tables 1 to 6 in relation to the parameter in question.
In the period from 1st July 1990 to 31st December 1990, the number of samples taken shall be not less than one-half of the standard number of samples so specified, which number shall be rounded upwards, if necessary, to the nearest whole number.
For the purposes of the application of paragraphs (1) and (2) to the parameters listed in Table 1 or 2 or referred to in Table 5, a supply which consists of both ground water and surface water shall be deemed to be a supply which consists only of surface water.
Where in each of three successive years the requirement mentioned in paragraph (5) below is satisfied in relation to a parameter listed in Table 1, 2 or 3 or referred to in Table 5 and the water authority is of the opinion that the concentration or value in respect of that parameter is unlikely to increase or, in the case of hydrogen ion, total hardness or alkalinity, decrease to any significant extent in the next following year, the number of samples to be taken in that year in respect of that parameter may be the reduced corresponding number:
Provided that this paragraph shall apply in order to determine the number of samples to be taken in 1991, 1992 and 1993 with the modifications specified in paragraph (6) below.
The requirement referred to in paragraph (4) above is that analysis of each sample taken in relation to the parameter in question in accordance with paragraph (1) or (2), as the case may be, has established—
in the case of hydrogen ion, a pH value that is no less than 6.5 and no more than 8.5;
in the case of total hardness or alkalinity (where water has been softened or desali nated), a concentration that is no less than 90mg Ca/1 or 45mg HCO3/1, respectively; or
in any other case, a concentration or value which is less than 50% of the prescribed concentration or value.
Paragraph (4) shall apply in order to determine the number of samples to be taken—
in 1991 as if it referred to the period from 1st July 1990 to 31st December 1990 instead of three successive years;
in 1992 as if it referred to the period from 1st July 1990 to 31st December 1991 instead of three successive years;
in 1993 as if it referred to the period from 1st July 1990 to 31st December 1992 instead of three successive years; and
in each of these years with the substitution of “and the Secretary of State has notified the authority that he” for “and the water authority”.
Where—
the result of the analysis of any sample taken in accordance with paragraph (1) or (2), as the case may be, has established in relation to any parameter listed in Tables 1 to 5 that the prescribed concentration or value has been contravened; or
as a consequence of any change in a water authority’s practices as regards the treatment of water (whether at a service reservoir, treatment works or otherwise), the authority is of the opinion that the prescribed concentration or value in respect of any parameter has been or may be contravened,
the number of samples to be taken in respect of that parameter—
in the remainder of that year and the following year; or
in such longer or shorter period as the Secretary of State may specify by notice in writing given to the water authority,
shall, where an increased corresponding number is shown in relation to that parameter, be the number determined in accordance with paragraph (8).
The number determined for the purposes of paragraph (7) is—
for any whole year in the period the increased corresponding number; or
for any other part of the period the increased corresponding number multiplied by the number of whole months in that part and divided by 12; and, where the result is not a whole number, rounded upwards to the nearest whole number.
Where an analysis of samples taken in accordance with paragraph (7) demonstrates that there has been no contravention of the prescribed concentration or value in the relevant period, the authority may revert to sampling in accordance with paragraph (1).