Water entering a wastewater collection system must, except in the case of unusual situations, particularly those due to heavy rainfall, be subjected to treatment before being discharged into the natural environment, under the conditions set out in articles R. 2224-12 to R. 2224-17 below.
An order of the ministers responsible for health and the environment sets the minimum technical requirements to ensure the effectiveness of wastewater treatment, in particular with regard to “biochemical oxygen demand” (BOD), “chemical oxygen demand” (COD), suspended solids (SS), phosphorus and nitrogen.
When the installation is subject to authorisation or declaration pursuant to articles L. 214-2 to L. 214-6 of the Environment Code, the minimum technical requirements provided for in the previous paragraph may be supplemented or reinforced by prefectoral orders issued in application of articles 13 and 15 of decree no. 93-742 of 29 March 1993 or measures issued in application of articles 31 and 32 of the same decree.