When the indicative values defined in article R. 1321-3-1 and the vigilance values defined in article R. 1321-15-1 are not met and the Prefect, on the report of the Director General of the Regional Health Agency, considers that the distribution presents a risk to human health, he asks the person responsible for producing or distributing the water to take corrective measures to restore the quality of the water. The latter informs the mayor of the measures taken, and the director general of the regional health agency, who forwards this information to the territorially competent prefect.