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Water quality study: Correction of inverted connections would promote access to swimming in Repentigny

Échantillonnage à Repentigny


Montreal September 8, 2023 – The Rivières Foundation unveils the results of a study on the bacteriological quality of water from the St. Lawrence River and the Assomption River in Repentigny. The City of Repentigny mandated the non-profit organization to evaluate the potential for swimming and nautical activities by identifying sources of contamination to increase the accessibility of the banks to the population as part of the adoption of its environmental policy.


The data collected in the summer of 2022 does not allow us to conclude that the water was suitable for swimming, particularly due to the reverse connections. However, in 2014, the City of Repentigny adopted an action plan to carry out an inventory of these connections in order to improve water quality and comply with the requirements of the Quebec-municipality infrastructure program. To optimize its efforts, the Foundation recommends that it prioritize areas that could be used for swimming and other water activities.

Reverse connections are sewer pipes connected to the stormwater network, resulting in the discharge of untreated wastewater into the environment, whether in rainy or dry weather. This widespread phenomenon in Quebec occurs when a contractor makes a non-compliant connection of a new building to the municipal network.

As for activities without direct contact with water (canoe, kayak, paddle board, etc.), two of the four sites studied – Saint-Laurent Park and Île-Lebel Park – presented a quality of life. water meets the recommended threshold most of the time. In Quebec, the recommended threshold for swimming is 200 CFU/100 mL while that for indirect contact activities is 1,000 CFU/100 mL.

Need for electronic overflow recorders (EED)

Wastewater overflows are another source of contamination in Repentigny during rainy weather, but the Foundation was unable to identify which structures were problematic for possible access to water due to the absence of electronic water recorders. overflows (EED) on half of the overflow structures. The EEDs indicate the exact moment of overflows and their duration, essential conditions for the development of a protocol for closing a possible swimming area.

This problem is widespread in Quebec. Since 2014, article 9 of the Regulation respecting municipal wastewater treatment works (ROMAEU) requires that any overflow work which experiences an overflow not caused by an emergency must be equipped with an EED capable of to measure the frequency and cumulative daily duration of overflow.

“Being bordered by the St. Lawrence River and the L'Assomption River, Repentigny has a strategic position in terms of access to water. We feel that there is a clear and strong desire from the City in this direction. Now, we will be able to support the City in implementing our recommendations,” declares the general director of the Rivières Foundation, André Bélanger.

“We welcome with great interest the results presented by the Rivières Foundation. We are committed to giving Repentignoises and Repentignois full access to the two rivers that border their city. To do this, we first had to obtain a clear picture of the situation in order to properly guide our future actions. The results show that we are on the right track, since we have been carrying out an inventory of reverse connections in the territory for more than five years. We will make sure to continue our efforts in line with the recommendations so that the population can rediscover the pleasures offered by the river,” indicates the mayor of the City of Repentigny, Nicolas Dufour.


The Rivières Foundation took a total of 110 surface water samples at four regular monitoring sites, twice a week, between July and September 2022. In the river: at Saint-Laurent Park, at Parc de l'Île- Lebel and the North Shore marina. In the L'Assomption River: at Entramis Park. The analysis was carried out on the basis of the enumeration ofEscherichia coli (E.coli).

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Picture of Sophie Lachance

Sophie Lachance

Communications and Mobilization Manager
Fondation Rivières
514-272-2666, ext. 307

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