1.Member States shall ensure that sets of bathing water quality data are compiled through the monitoring of the parameters set out in Annex I, column A.
2.Bathing water quality assessments shall be carried out:
(a)in relation to each bathing water;
(b)after the end of each bathing season;
(c)on the basis of the set of bathing water quality data compiled in relation to that bathing season and the three preceding bathing seasons; and
(d)in accordance with the procedure set out in Annex II.
However, a Member State may decide to carry out bathing water quality assessments on the basis of the set of bathing water quality data compiled in relation to the preceding three bathing seasons only. If it so decides, it shall notify the Commission beforehand. It shall also notify the Commission if it subsequently decides to revert to carrying out assessments on the basis of four bathing seasons. Member States may not change the applicable assessment period more than once every five years.
3.Sets of bathing water data used to carry out bathing water quality assessments shall always comprise at least 16 samples or, in the special circumstances referred to in Annex IV, paragraph 2, 12 samples.
4.However, provided that either:
the requirement of paragraph 3 is satisfied, or
the set of bathing water data used to carry out the assessment comprises at least eight samples, in the case of bathing waters with a bathing season not exceeding eight weeks,
a bathing water quality assessment may be carried out on the basis of a set of bathing water quality data relating to fewer than four bathing seasons if:
the bathing water is newly identified;
any changes have occurred that are likely to affect the classification of the bathing water in accordance with Article 5, in which case the assessment shall be carried out on the basis of a set of bathing water quality data consisting solely of the results for samples collected since the changes occurred; or
the bathing water had already been assessed in accordance with Directive 76/160/EEC, in which case equivalent data gathered under that Directive shall be used and, for this purpose, parameters 2 and 3 of the Annex to Directive 76/160/EEC shall be deemed to be equivalent to parameters 2 and 1 of column A of Annex I to this Directive.
5.Member States may subdivide or group together existing bathing waters in the light of bathing water quality assessments. They may group existing bathing waters together only if these waters:
(a)are contiguous;
(b)received similar assessments for the preceding four years in accordance with paragraphs 2, 3 and 4(c); and
(c)have bathing water profiles all of which identify common risk factors or the absence thereof.