Versailles facing the degradation of its water supply from the Seine River: governance, water quality expertise and decision making, 1852–1894 Tatiana Dmitrieva 1 • Laurence Lestel 1 • Michel Meybeck 1 • Sabine Barles 2 Received: 4 July 2016 / Accepted: 9 May 2018 Ó Springer Science+Business Media B.V., part of Springer Nature 2018 Abstract In 1852 a new machine to provide greater volumes of Seine River water to Versailles was decided. The new Marly Machine was operated by the Versailles Water Service (VWS), a 150-year old state-owned institution supervised by state ministries, managing the water supply over a vast domain that covered 32 towns in 1903. The VWS provided financial, technical and administrative resources to the city of Versailles, but the city council had no word in decision-making. Soon after the installation of the Machine in 1859, the city of Paris started to collect its wastewaters and discharge them untreated into the river, 16 km upstream of the Marly Machine. In 1874 the Seine River was officially declared infected by Paris sewers. The VWS reacted in 1877 by asking several French chemists, pioneers of river surveys, to assess the quality of the Versailles waters by innovative chemical approaches that had been developed on the Seine River since the Boudet ammonia river profile in 1861. In 1874 Ge ´rardin’s oximetric profiles revealed the severe depletion of oxygen in the Seine at Marly in the summer, explaining the fish kills. This degradation of Versailles water intake in the Seine River mobilized local, regional and national actors over the coming 20 years. Finally, the VWS was forced to gradually use (1880–1895) groundwater to supply the Marly Machine. In 1892, another new water quality criterion was considered, the bacteriological survey, and in 1894 the Seine River water was completely excluded as a water source, ending a multidecadal debate in which scientific expertise played a prominent role. Keywords Water supply Á Versailles Á Marly Machine Á Seine River Á Water quality analysis & Laurence Lestel laurence.lestel@upmc.fr 1 Sorbonne Universite ´, CNRS, EPHE, UMR 7619 Metis, 75005 Paris, France 2 Universite ´ Paris 1, UMR 8504 Ge ´ographie-Cite ´s, 75005 Paris, France 123 Water Hist https://doi.org/10.1007/s12685-018-0216-7