Rankings and map of wastewater spills in Quebec
A tool to understand the scale of wastewater spills
The Wastewater Discharge Index presents the annual ranking of municipalities, from worst to best, according to the intensity of discharges per capita. Les déversements refers to untreated water discharged into rivers.
This exercise makes it possible to distinguish municipalities which have improved since the previous year from those where the situation has deteriorated, and to encourage elected officials to correct the problems. The ranking is made from the map of wastewater spills.
Ranking of cities and municipalities according to the spill intensity index per capita
Compare the cities and municipalities by size (small, medium, or large). This year, 726 municipalities are considered in the ranking.
Déversements d’eaux usées au Québec entre 2017 et 2024
Discover the evolution of the performances of the 700 municipalities of Quebec according to the spill intensity index.
Map of wastewater discharges
Map of wastewater discharges donne un portrait plus global de la situation: y sont répertoriés le nombre des déversements et leurs durées totales annuelles sur le territoire des municipalités. Celles-ci sont tenues par la loi de fournir ces informations au ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (MELCCFP). La carte interactive s’appuie d’ailleurs sur les données du MELCCFP.
Understand how the map works
Credits and acknowledgements
The wastewater map is based on the data colligées par le MELCCFP entre 2011 et 2022. L’extraction de données et leur organisation a été rendue possible grâce au AuditEAU, a wastewater management software développé par notre équipe avec l’appui de Charles de Grandpré. La première mouture a bénéficié de la contribution d’étudiant.e.s from UQAM's journalism program and media school, under the supervision of the teacher Jean Hugues Roy.
Wastewater management in Quebec: an issue of adaptation to climate change
Significant quantities of wastewater are discharged into Quebec's rivers every day because they cannot be treated by municipal sewage systems. Heavy rains, insufficient capacity and failure (cross-connections) of sewer systems, under-investment by the government, urban development without consideration for the environment: the causes are multiple.
Climate change is not helping the situation. According to Ouranos, episodes of heavy rain will be more intense and more frequent, resulting in flooding and overflows due to overloading of sewer networks.
What are the solutions to stop spills?
Spill Reduction Objective
Quebec does not have an overall objective for reducing wastewater discharges. The Ministry of the Environment asks municipalities not to increase the number beyond that of 2013 and even gives them until 2030 to do so. Instead, it should encourage them to reduce spills, as some municipalities are already doing!
Strategic financing of municipal infrastructure
By allocating funding to municipalities based on the impact on their receiving environment rather than on a first-come, first-served basis, the Ministry of Municipal Affairs and Housing (MAMH) would greatly contribute to the solution.
Proper Spill Measures
Measuring spills correctly is essential to have a clear picture of the situation and be able to act at the source. However, nearly 200 municipalities do not do it even though it has been obligatory for almost 10 years. The Ministry of the Environment imposes almost no sanctions. If cities were monitored, they would certainly be more likely to comply with the regulation.
Territory Development
More green infrastructure and less impermeable (concrete) surfaces would reduce pressure on sewer networks. The absorbent power of plants would limit rainwater runoff. Also, the Real estate development must be done in harmony with the capacity of the network. Some cities do not hesitate to impose a moratorium on development, a bold and exemplary gesture!
