BWD - Article 5.4
However, notwithstanding the general requirement of paragraph 3, bathing waters may temporarily be classified as ‘poor’ and still remain in compliance with this Directive. In such cases, Member States shall ensure that the following conditions are satisfied:
(a) in respect of each bathing water classified as ‘poor’, the following measures shall be taken with effect from the bathing season that follows its classification:
(i) adequate management measures, including a bathing prohibition or advice against bathing, with a view to preventing bathers' exposure to pollution;
(ii) identification of the causes and reasons for the failure to achieve ‘sufficient’ quality status;
(iii) adequate measures to prevent, reduce or eliminate the causes of pollution; and
(iv) in accordance with Article 12, alerting the public by a clear and simple warning sign and informing them of the causes of the pollution and measures taken, on the basis of the bathing water profile.
(b) If a bathing water is classified as ‘poor’ for five consecutive years, a permanent bathing prohibition or permanent advice against bathing shall be introduced.
However, a Member State may introduce a permanent bathing prohibition or permanent advice against bathing before the end of the five‑year period if it considers that the achievement of ‘sufficient’ quality would be infeasible or disproportionately expensive.