Paris Water Quality and the River Seine

Published 05/14/2024 in Scholar Travel Stipend
Written by Asha Goyal | 05/14/2024

The Seine winds through the heart of Paris, carrying centuries of history and culture. People stroll, boats tour, and buildings look out onto this iconic waterway. The Seine embodies Parisian charm. Paris plans for the river Seine will get its moment to shine on the world stage with the upcoming Olympics. City officials are hoping for the swimming leg of the triathlon event to take place in the Seine. However, there are issues with Paris’s water management that currently make the river unsafe to swim in.

Will the Seine be clean in time for the Olympics? My recent trip to France examined this question of Paris water management—wastewater treatment, stormwater pollution, and sewage management.

While in Paris, I visited the Musée des Égouts de Paris where I toured the sewers and learned about the history of water management in the city. Currently, the sewers contain “2600 km of galleries and gutters. Some 300 million qm3 of rainwater and wastewater pass through them every year, hurtling down the pipes of this singular, gravitational and visitable network” (Musee). Paris water is not cleaned with chlorine, unlike most major treatment plants. The water goes through a screening where debris is filtered out, then filtration and “polishing” which uses ozone and UV light. Before the sewer system, there was a high mortality rate due to lack of hygiene, overflowing sewers, and water contamination: the cholera epidemic caused 18,000 deaths. Before the implementation of the system, sewage was released into the streets and the Seine. Working class people lived amongst filth and dirty water that led to many diseases.

In Sewer Museum2Paris developed its first sewer system in 1833, with the purpose of collecting rainwater. Once the sewers were built, water was able to flow beneath the city. Paris’ waste also flows through this underground network, eliminating the waste throughout the streets. Sewage, which was seen as an effective fertilizer, was then sent to farms to fertilize crops during the 1800s. Throughout the rest of the century, Paris made improvements with capturing and distributing fresh water. Starting in the early 20th century, the sewers contained pipes for drinking water, non-potable water, and even pneumatic letters.

Once the sewers were built, work had to be done to keep the system clean and functioning. Eugene Belgrand worked to distribute and recover pure water throughout the city through underground lines. Belgrand also created cleaning apparatus, such as the valve boat for large collectors, wagons for small collectors, and machine injectors. These tools are still in use today.

While Paris is currently making improvements on its water processing systems, the Seine is not safe enough to swim in: “Surfrider Foundation Europe completed 14 tests on water samples taken from two spots on the river between September 2023 and March 2024 and found all but one showed poor water quality” (CBS). The triathlon safety standard is 1,000 e coli for 100ml of water. According to recent tests, the Seine contains 20,000 e coli for each 100ml of water—twenty times the standard for swimming (WSJ). These tests were taken in colder, rainer months, and Paris officials claim that the Seine is cleaner in the summer due to UV light killing the e coli and the lack of rain leading to wastewater overflow in the Seine. During heavy rains, the single system infrastructure does not have enough capacity to handle the influx of water, and the polluted water is drained into the Seine. Paris is willing to push back the triathlon to ensure the race can take place in the Seine, and water will be tested everyday of the Olympics (Reuters).

According to Forbes, Paris has spent more than $1.5 billion to clean the Seine for public use. This effort was initiated over thirty years ago, and the pressure from the Olympics serves as a motivator. A Paris 2024 spokesperson claims that “By the time the Games start, the efforts to clean up the river ‘will have reduced bacteriological pollution by 75%’” (CBS).

Currently, wastewater and rainwater flow into the same drainage pipes. To remedy this, Paris built a 15 million gallon underground tank to store water. The tank, build next to the Austerlitz train station, will be a holding place until the water can be sent to a treatment plant. Once clean, the water will be fed into the Seine. This will prevent dirty stormwater from entering the river. Pauline Levaud, Paris mayor's advisor on water and maintenance of public spaces, told reporters “We are now back to the level of sanity of the pre-industrial era . . . the Olympics have made us gain 10 years on our project of making the Seine bathable” (Reuters). There are also now thirty types of fish found in the river, compared to the 1980s when only two types could be found. 

During my travels, I took a boat tour on the Seine river. Throughout the tour, I was educated on the history of the city in relation to the buildings surrounding the Seine. The tour guide talked about how the Musee d’Orsay was once a train station, that Paris has a miniature version of the Statue of Liberty, and that Pont Alexandre III is the most ornate bridge in the city. Looking out onto the Louvre, Musée d’Orsay, and Notre Dame, I realized how central the Seine is to Parisian culture. Many major attractions fall along this river. As Paris presents the best version of itself to the world, it makes sense to feature the Seine. However, the Seine must be cleaned in order for Paris to properly show off the river.

The Olympics provide host cities with funding and attention to fix major issues plaguing the city. The pressure from the Olympic committee catalyzes Paris to clean up its waterways. The Milken Institute’s focus on environmental health and motivation to tackle “some of our most critical global issues through the lens of what’s pressing now and what’s coming next” motivated me to focus on this environmental issue of water quality. As Paris gears up for the Olympics, it must focus on the city’s environmental health and its ability to support and safeguard the influx of tourists and athletes from across the globe. Paris’s success in cleaning the Seine can also be used as a model for cities across the world. However, I doubt the 2028 Olympics triathlon will feature the Los Angeles River.

On the Ponte de Alexandre III bridge 

Asha Goyal on the Ponte de Alexandre III bridge.


Bisserbe, Naomi and Eve Hartley. “Herculean Feat in Paris Olympics: Make the Seine Safe to Swim.” 2 April 2024, “History of the Sewers of Paris.” Egouts de Paris,  

O’Kane, Caitlin. “Alarming Levels” of Bacteria like E. Coli in Paris’ Seine River Present a Challenge for Olympic Swimming Events - CBS News. 13 Apr. 2024,

Pretot, Julien. “Paris 2024 Banks on Further Improvements to Make River Seine Suitable for Swimming.” Reuters, 30 Nov. 2023.,