Grenoble Alpes Métropole is responsible for collecting and treating the sewage produced by its member communes and other communes associated either directly or through an intercommunal organisation.

• To build a number of new main sewers to intercept the communal or intercommunal sewers situated upstream, to transport the sewage to the treatment plants.
• To build plants for treating the sewage before it is discharged into the river Isère, in line with the prescribed standards for sewage discharge.
• To oversee the functioning of all sewage works.

The construction of the main sewers and the first treatment plant, known as the Fontanil plant, took place between 1972 and 1988.

• A network of approximately 35 kilometres of sewers of diameters of up to 2.20 m, with their accompanying installations: 32 pumping stations (discharge and lifting) designed to assist the flow of sewage to the treatment plants.
• The Fontanil treatment plant, commissioned in 1977, which mainly treats the waste water discharged from Grenoble's abattoirs, together with the sewage from the communes of Le Fontanil-Cornillon, Saint-Egrève and Saint-Martin le Vinoux. Its capacity is estimated to be a population equivalent of approximately 35,000.
• The Aquapôle treatment plant, commissioned in 1989, which treats the sewage from the entire Grenoble agglomeration: population equivalent of 500,000, 100,000 of which is industrial.