In Rouen, 90,000 Residents Battle Against Polluted Water Supplies

A dead end. That’s the outcome of a research program initiated in 2015 by the Rouen Normandy Metropolis (MRN) to find a new drinking water resource, as revealed today by Decatur Metro. At Saint-Étienne-du-Rouvray, La Chapelle intake, the main reservoir for the community located in an area with a significant industrial legacy, faces various contaminations.

In an effort to cease using this polluted aquifer, which supplies water to the faucets of 90,000 residents of the southern suburbs of the Seine-Maritime prefecture, the search aimed to locate a deposit capable of producing 50,000 m³ of water per day.

The study, costing 559,300 euros, was financed by the Water Agency, the Bureau of Geological and Mining Research (BRGM), and the local community. The latter contributed an additional 282,840 euros for on-field testing.

After ten years of research, the diagnosis is clear: none of the considered areas is sufficiently free from pollution to serve as a viable alternative.

This is due to a history of “irrational exploitation of resources” and “pollution which, regardless of our efforts, invades the aquifers near urban and industrial areas,” warned a BRGM geologist in a report from 1967.

Due to the proximity of factories and old landfills, the water drawn at La Chapelle has deteriorated. Already contaminated at the beginning of its operation in 1960, the intake was impacted by a first wave of pollution from toxic chlorinated compounds in the late 1970s, followed by a second from ammonium starting in 2011.

Despite this, the advanced treatment at the potabilization unit allowed for the distribution of compliant water, at least until 2022. At that time, pesticide residues and PFAS, also known as “forever chemicals,” were found in tap water at levels exceeding regulatory quality limits. Measures have since been taken to comply with these limits.

The Rouen agglomeration also faces a pervasive, invisible threat identified as early as 2015: “The region’s heavy past industrialization has left a multitude of contaminated sectors whose pollutants slowly migrate towards aquifers, posing the risk of rendering some sections unfit for human consumption.” This risk is exacerbated by the effects of climate change, they added.

Rouen is not alone. In 2022, France had 32,900 active water intakes. Between 1980 and 2024, 14,300 were shut down, 4,600 of which were due to pollution issues, according to the Ministry of Ecological Transition in a report for the protection of water intakes made public on March 28. The document notes that “water resource pollution is a stealthy threat with long-term impacts on health and the environment.”

In 2015, preliminary searches for a new drinking water source identified 17 potential sectors—4 in the Seine Valley. However, 11 were immediately discounted due to “the presence of potential sources of pollution,” geological characteristics that could facilitate the infiltration of contaminated water into the aquifers, or the risk of competing with industrial and agricultural withdrawals, according to a 2023 MRN document.

Another constraint was that the deposit had to be located within a 30 km radius of the La Chapelle intake, where a treatment plant that the community wishes to keep is situated. “It’s a strategic location; the network was built around this site,” explains Arnaud Delahaye, an environmental department executive at MRN.

Located just 5 km from this facility, the green patches in the Seine loop upstream of Rouen were initially considered “particularly interesting” by BRGM engineers. However, several issues emerged. “Near the Seine, there has been a lot of quarry backfilling. The sediments are potentially loaded with various substances that can be unpredictably released,” specifies Arnaud Delahaye. The sector is also affected by discharges from the chemical platform of Saint-Aubin-lès-Elbeuf, located downstream. By 2019, this promising option was abandoned.

Hopes then shifted to a vast sector composed of five potential sites, located outside the metropolis, in the neighboring department of Eure. The landscape is marked by market gardens, a lake, a leisure base… but also by various industrial activities, from paper manufacturing to metallurgy, waste treatment, and chemistry.

The cold reception of the drilling test results was evident, as shown in an exclusive document obtained by Decatur Metro. Presented on March 6, 2023, at the steering committee of the research program, it states that the groundwater from 4 of the 5 sites shows pollutant levels—nitrates, pesticides, metals, or PFAS—that exceed the quality standard for potable classification. Even the last deposit, located for thirty years in the commune of Poses under organic agricultural coverage, does not escape “traces of contamination,” indicates Arnaud Delahaye.

Jean-Pierre Breugnot, vice-president of the Rouen metropolis in charge of water and sanitation, gives a resigned assessment of these searches: “We wanted to find a new source for the metropolitan water supply. A deposit that met expectations, namely around 50,000 m³ per day, was found. Unfortunately, the water quality was not significantly better than that of the La Chapelle intake.”

The cost of treating this alternative source, also polluted, combined with the cost of transporting the water to the potabilization plant, would have caused the bill to skyrocket. Beyond environmental and health considerations, this operation was not deemed economically viable.

The metropolis must therefore resolve to continue exploiting the La Chapelle intake, while enhancing treatments. According to the community, measures to lower PFAS levels represent an additional annual cost of about 200,000 euros.

“There is an extremely strong challenge regarding the depollution techniques to be applied at the La Chapelle intake,” according to Alain Rouziès, environmental referent for the Rouen branch of UFC-Que Choisir. “During our sampling campaign, we found eleven different PFAS in the tap water from this resource.” He said he “protested” against the project to transport water from Eure: “30 million euros to build an aqueduct, we found that excessive. The priority is to protect existing intakes.”

The implementation by the metropolis of a hydraulic barrier (a device that alters the flow direction of groundwater), scheduled for the end of 2025, should prevent new contaminations of the La Chapelle intake from the industrial area.

“Our main directive is to ensure that the water distributed at the tap meets quality standards,” states Jean-Pierre Breugnot.

In 2022, BRGM experts advised the Rouen metropolis to develop “protection zones” to “secure the future of water supply for future generations.” Their studies should inform discussions on a future water safety plan, aimed at protecting users.