Background The SIAH wastewater plan has to cope with an increasing quantity of urban wastewater, in an area under rapid urbanisation and constant population pressure. Anticipating is a key element to keeping infrastructures suitable for wastewater and rainwater treatment. As an interface between wastewater discharges and the environment, the cleaning system is exposed to an increasing quantity and diversity of chemical products used by the industry. These may damage both the networks and the water treatment stations. Further downstream, this also has a negative impact on the environment. Technically speaking, the management quality of pipe connections is sometimes weak and the absence of centralised data makes it difficult to monitor the system properly. Objectives The main aim of the project was to develop an integrated pollution prevention approach including all cleaning system users by linking quantitative data and combining them with a GIS (Geographic Information System). Through the ECOSEN Life project, the inter-municipal association intended to: - encourage environmental management among its members by introducing EMAS and achieving ISO 14001 certification; - centralise quantitative data in order to build an accurate computerised monitoring system and introduce effective reporting from the purification system; - provide the industrial companies with technical support and exchange of information; and - transfer the experience and skills to professionals in France and Europe. Results The project was initiated and supported by the SIAH’s then director, who was highly committed to environmental issues. His death in early 2003 had a destabilising effect on the company structure, the project team and the project’s implementation. Due to management difficulties, the foreseen actions could not begin in due time and the project as a whole was delayed. The project ended in December 2005 having only partly achieved its original objectives. The computerised system may be an asset in the future, but to date it’s not possible to assess as it is not yet operational. The environmental management tools for SIAH were developed and procedures were thoroughly revised. This should lead to a future EMAS certification. Though some communication activities targeting the general public were implemented at the local level, awareness-raising among the diverse stakeholders was not undertaken.