The Turbidity and Gastroenteritis Study aims to establish and characterize the link between the turbidity level of distributed water and the number of cases of acute gastroenteritis (AGE) observed in the service area. This component of the study covers three municipalities within the Angoulême community of municipalities, which are supplied with water from the Touvre springs. This water source is considered one of the largest karstic resurgences in France. The water treatment plant’s process included coagulation via sand filtration followed by disinfection through chlorination. The incidence of waterborne diseases was derived from health insurance data between 2002 and 2007. The method involved regressing, using a generalized additive model, the incidence of waterborne diseases against daily turbidity levels of the distributed water. In a second step, several plant operating parameters or meteorological factors were tested as risk factors for AEFs. The results do not reveal a link between the deterioration in the turbidity of water produced by the Touvre plant and the incidence of AEFs in the Angoulême metropolitan area. Nevertheless, since we have identified a significant link between the deterioration in the turbidity of the source water and the incidence of GEA, we assume that certain technical aspects of the treatment process used at Touvre prevented us from demonstrating a statistical association that likely exists. The daily flow rate produced influences the level of endemic risk of GEA. (R.A.)