In 2019, Santé publique France launched, in partnership with the Directorate General for Health (DGS) and the regional health agencies (ARS), the EpiGEH surveillance system, designed to monitor waterborne acute gastroenteritis (AGE), i.e., cases linked to the consumption of tap water. The purpose of this system is to guide management measures by identifying at-risk water systems. It includes a step to detect clusters of AGE cases with a plausible waterborne origin, conducted retrospectively by Santé publique France every four months; a step to validate the detected signals; and an environmental investigation step involving the ARS. After four years of implementing the EpiGEH system, Santé publique France initiated an evaluation process. The regional health agencies (ARS) were then asked to describe their level of knowledge and involvement in the system, as well as to identify areas for improvement. Between December 2023 and January 2024, an online survey was launched on the Lime Survey platform. It was sent to ARS staff likely to be involved in the surveillance and investigation system (staff from environmental health and health monitoring and safety departments). At the end of the data collection phase, 139 questionnaires were included in the data analysis (53% response rate). Among the key findings, it is worth noting that for 95% of respondents, the issue of drinking water was a public health priority in their geographic area, with 64% citing the existence of microbiological non-compliance in certain distribution networks as the reason. Regarding EpiGEH, 93% of respondents (N=129) were aware of the system, but only 45% (N=58) reported participating in it, 83% of whom were involved in conducting environmental investigations (N=48). Regarding these environmental surveys, 30 respondents reported having already participated, with the majority having already used the survey questionnaire; 85% of users reported being “fairly satisfied” to “very satisfied” with the current questionnaire, and nearly half found it useful in the context of their health monitoring activities or during facility inspections. It is worth noting that among the information collected directly from drinking water producers and distributors as part of these environmental surveys, 50% of the malfunctions or problems identified had not been reported to the ARS at the time they occurred. This assessment also highlighted regional inconsistencies in the implementation of EpiGEH and identified several bottlenecks. Areas for improvement can already be proposed, including strengthening regional coordination and expanding training offerings on the various components of the system. In line with the identified areas for improvement, a working group comprising volunteers from the ARS and Santé publique France is expected to be formed in 2025. It will contribute to refining the algorithm that assesses the plausibility of a waterborne origin for signals investigated under EpiGEH, as well as to updating the questionnaire used for environmental investigations.