10.—(1) After the end of every bathing season, for every bathing water, the Agency must—
(a)prepare a set of bathing water quality data for that season; and
(b)carry out a bathing water quality assessment using the set of bathing water quality data compiled in relation to that season and the relevant assessment period.
(2) In this regulation, the “relevant assessment period” is—
(a)the immediately preceding three bathing seasons;
(b)the immediately preceding two bathing seasons, if the Agency so determines in accordance with paragraph (3); or
(c)the number of immediately preceding bathing seasons, being less than three, that the Agency determines in accordance with paragraph (4).
(3) The Agency may make a determination under paragraph (2)(b) where—
(a)it has consulted the appropriate Minister; and
(b)it is at least five years since the last change in the relevant assessment period.
(4) The Agency may make a determination under paragraph (2)(c), if—
(a)it has consulted the appropriate Minister;
(b)the set of bathing water quality data used is based on at least 16 samples; and
(c)it considers that any factors identified in the bathing water profile as likely to affect the classification of the bathing water under regulation 11 have changed, and the set of bathing water quality data used is based only on samples taken since those factors have changed.