Article 3 9.

Member States shall ensure that the analysis of bathing water quality takes place in accordance with the reference methods specified in Annex I and the rules set out in Annex V. However, Member States may permit the use of other methods or rules if they can demonstrate that the results obtained are equivalent to those obtained using the methods specified in Annex I and the rules set out in Annex V. Member States that permit the use of such equivalent methods or rules shall provide the Commission with all relevant information about the methods or rules used and their equivalence.