Surface water whose physical, chemical and microbiological characteristics exceed the quality limits for raw water set by the decree mentioned in II of article R. 1321-7 may not be used for the production of water intended for human consumption. However, the use of water of such quality may exceptionally be authorised by the Prefect, in application of articles R. 1321-7 to R. 1321-9, when the following two conditions are met:
1° Appropriate treatment, including mixing, is used to bring all the water’s quality characteristics down to a level that complies with the quality limits set in the order mentioned in article R. 1321-2 or with the maximum acceptable values set by the derogation granted in application of article R. 1321-31;
2° A water resource management plan has been defined within the zone concerned, except for certain parameters mentioned in the order provided for in II of article R. 1321-7.
If the request for an exceptional authorisation to use surface water provided for in the first paragraph is kept silent for more than six months, this will be deemed to constitute a decision to accept it.