Compliance with guideline values
6.—(1) Subject to paragraphs (2) and (3) below, any waters classified under these Regulations shall be treated as complying with the limit specified in Schedule 2 for waters of the relevant class in relation to a parameter if–
(a)90 per cent of the samples taken in relation to the waters in accordance with regulation 9 below comply with the standard;
(b)none of the samples fails the standard by more than 50 per cent;
(c)there is no danger to public health; and
(d)consecutive samples taken at statistically suitable intervals do not exceed the standard.
(2) Non-compliant samples shall be ignored for the purposes of paragraph (1) above if they are the result of a flood, natural disaster or abnormal weather conditions.
(3) Paragraph (1)(b) above shall not apply in the case of the limits specified in Schedule 2 in relation to temperature, pH, dissolved oxygen and microbiological parameters.