Updated 11/07/2025
Update on July 11, 2025
Table of Contents
The entire department of Ille-et-Vilaine is placed on drought alert from July 11, 2025 whatever the water resource used (drinking water, wells, direct debit, etc.). This state implies restrictions, even prohibitions, for certain uses of water.
Due to a particularly dry spring, the department of Ille-et-Vilaine has been in drought vigilance since June 13, 2025. The situation is getting worse despite some very localized thunderstorms. After the heat wave last June, the weather forecast announced about fifteen dry and warm thus waving a degradation of the state of water resources (watercourse, tablecloths, water reserves of the dams) and an aggravation of the drought of the soil.
The flow rates of watercourses are rapidly decreased throughout the department. In the north of the department, the level of dams intended to produce drinking water is below the alert rating and we approach a situation similar to the east of the department.
This situation led the members of the Department’s water management committee, gathered in plenary session on July 8, 2025, to unanimously recommend the department’s classification, regardless of the origin of the water used, in drought alertsecond possible classification state to qualify the drought risk. For the record, the four growing criteria of concern about drought are: alertness, alert, reinforced alert and the crisis.
The prefect thus classified the department on drought alert, by prefectural decree of July 11, 2025.
The decree prescribes restriction and prohibition measures which essentially aim for the following uses:
- Cleaning facades, terraces, walls, stairs, roofs, vehicles including boats,
- emptying and filling in private family and collective pools,
- watering gardens, green spaces and sports fields,
- Power of beaches showers,
- the supply of the approval fountains,
- the use of drinking water in the various processes relating to industrial uses,
- l’irrigation agricole,
- Operational recognitions, maneuvers and exercises of the departmental fire and rescue service,
- Periodic technical controls, purges and tests of fire posts,
- the maneuver of valves that can influence the hydrographic network.
To facilitate access to information and measures applicable in each municipality, the State provides the Vigieau tool.
- Information about water restrictions during drought period: Vigieau
It is possible to register on this site to be alerted as the real restrictions applying to your municipality.
Beyond the restrictions imposed regulations, All users (individuals, communities, industrialists, farmers) are called upon to voluntarily reduce their water consumption, whatever its origin (public drinking water network, levy in the natural environment, etc.).
Update on June 17, 2025
The department was classified in a state of drought vigilance, by prefectural decree of Friday June 13, 2025. This decision follows a significant deterioration of hydrological conditions on the territory. All users are thus called to vigilance concerning their water consumption.
Although Ille-et-Vilaine experienced rains twice higher than normal in January 2025, even causing an episode of major floods, the department has displayed a significant rainfall deficit since the beginning of the year. This deficit varies from 30 % in the center and the south of the territory to almost 70 % on the coast. These weather conditions lead to a significant drop in watercourses’ flow rates, which threatens aquatic life. We also observe an early destocking of the dams which ensure the supply of drinking water, as well as an exceptional drying of the floors.
This situation, although not critical at this stage, is worrying. This is why the members of the Department’s Water Resource Management Committee, gathered in plenary session on June 4, 2025, unanimously recommended the department’s ranking in a vigilance situation. This is the first level of classification of drought risk, before the alert, the reinforced alert and the crisis.
In order to preserve the resource, all users – individuals, industrialists, communities and farmers – are invited to reduce their water consumption, whatever its origin (public drinking water network, samples in the natural environment, etc.).
To facilitate access to information and measures applicable in each municipality, the State provides the Vigieau tool.
- Information about water restrictions during drought period: Vigieau
