In the 1980s, the migration of chemical waste into the soil at the Solvay plant in Tavaux (Jura) caused long-term contamination of the groundwater. The contamination, monitored by a piezometric network, extends across four inhabited municipalities directly affected by the pollution. A cross-sectional survey was conducted by the Franche-Comté Regional Health Observatory (ORS) during the summer of 2007 on behalf of the Regional Unit of the French Institute for Public Health Surveillance (InVS) in the Bourgogne-Franche-Comté region (Cire). Residents of the five municipalities were contacted by phone or mail to gather information on household and well characteristics, well water uses, and potential occupational exposure to the chemicals found in the contamination. Of the 528 households surveyed, 189 (36%) had a private well. The most common use was watering a vegetable garden, followed by washing vehicles, filling a swimming pool, and connecting to plumbing fixtures. The least common use was consuming the water as drinking water. The use of well water for various purposes was therefore widespread among residents of the four municipalities. Despite restrictions on water use, habits have persisted. These results serve as a reminder that while an administrative decision demonstrates the government’s intent, a often delicate phase of communication and awareness-raising must follow so that, ultimately, public action can lead to a change in behavior among those at risk. (R.A.)