From the standpoint of sustainable development, the Master Plan favours the consolidation of existing urbanized areas that are already served by water and sewer systems. However, the current condition of these networks requires major restoration work. More specifically, in many places, the deterioration of the water infrastructure has led to leaks and breaks in the network. As a result, water must be treated in quantities much greater than the actual demand.

In 2003, the City released its Politique de gestion de l’eau (Water Management Policy), whose main measures aim to restore the water infrastructure and reorganize water systems and their financing. Among other efforts, the policy calls for bringing water treatment plants up to specific standards and, by 2022, upgrading roughly 3,000 kilometres of the City’s 5,000-kilometre network.

Wastewater interception and treatment, which began 30 years ago, has substantially improved water quality in Montréal. In Lac Saint-Louis, Bassin de La Prairie, the Port of Montréal and more recently Rivière des Prairies, the improvement is so great that recreational uses are possible once again.

However, problems of a more technical nature will require substantial investments by the City in the years ahead. These are partly related to the current condition of the storm and sanitary sewer systems, including:

• Collector sewers overflowing during heavy rain;
• Sanitary sewers connected to the storm sewer collector in some buildings;
• The absence of connections between sanitary sewers and the treatment plant in some areas;
• Discharges of industrial contaminants that cannot be treated by the City’s wastewater treatment plant;
• The absence of wastewater disinfection.