Map of aquifer levels in mainland France on 15 August 2025.
© BRGM
Trends observed on piezometers on 15 August 2025.
© BRGM
89% of levels were lower on 15 August 2025 compared with 88% at the end of June. Groundwater reserves declined everywhere.
The rainfall in the second half of July had little impact on the aquifers. The infiltration of rainwater moistens the soil and is mostly taken up by vegetation. However, the rate of depletion was slowed by local, sporadic recharge episodes and by a more or less significant decrease in abstractions. In August, trends began to decline again, cancelling out the benefits of July's rainfall.
Depletion was significant in areas with little rainfall: the north and centre of the Massif Central and the south-west.
Situation observed on piezometers on 15 August 2025.
© BRGM
Aquifer situation
The situation remained generally stable between the reports of 1 August and 15 August. It is improving slightly in areas that experienced heavy rainfall in July and have reactive aquifers, i.e. the Sologne and Sancerre, the eastern edge of the Paris Basin and Côte-des-Bars, and the Causses du Quercy. The status of aquifers in the Massif Central basement (particularly in Limousin) continues to deteriorate, with no effective rainfall for several weeks.
The groundwater situation varies according to the total amount of rainfall in recent months and the aquifer’s reactivity:
- satisfactory for inertial aquifers (Paris Basin, Rhône-Saône corridor) and for reactive aquifers in the Armorican Massif, the Aquitaine Basin, the south and Corsica;
- below monthly averages for reactive aquifers and less inertial aquifers in the north (Artois and Boulonnais coast) and north-east (north and centre of the Massif Central, Jura and Grand-Est);
- very unsatisfactory levels in Roussillon, the Corbières Massif and the alluvial deposits of the Aude valley.
Forecasts
For the end of summer, forecasts are dependent on groundwater demand due to abstraction and, for reactive aquifers, on a possible boost from effective rainfall. The storms that usually occur towards the end of summer are expected to have an impact only on the most reactive aquifers (basement and karst limestone). Recharge episodes are nonetheless expected to remain, initially, sporadic and of little significance.
In autumn, forecasts depend on the occurrence of heavy rainfall and the dormancy of vegetation, i.e. the start date of the recharge period. In the event of a late recharge (November), low to very low levels could become widespread in reactive aquifers whose levels are currently below average. Finally, forecasts remain highly pessimistic for the aquifers of the Roussillon plain.
Groundwater situation: a new map and more frequent bulletins
The BRGM groundwater status report, which is eagerly awaited by the public every month, is being revamped. It will now be published twice a month, and the map will have a new colour scheme to make it easier to read.
As of 1 July 2025, the comparative map between the current month and the same month of the previous year will also be reissued with the new colour scheme.
Map drawn up by BRGM on 20 August 2025, based on data acquired up to 15 august 2025.
Data source: ADES database (ades.eaufrance.fr) / Hydroportail (hydro.eaufrance.fr) / Background map © IGN. Data producers and contributors: APRONA, BRGM, Conseil Départemental de la Vendée, Conseil Départemental des Landes, Conseil Départemental du Lot, EPTB Vistre Vistrenque, Parc Naturel Régional des Grandes Causses, Syndicat Mixte d'Etudes et de Travaux de l'Astien (SMETA), Syndicat Mixte pour la protection et la gestion des nappes souterraines de la plaine du Roussillon (SMNPR).
This map shows the global indicators reflecting the average fluctuations of the aquifers. They are based on point indicators collected at groundwater monitoring points (by means of piezometers).
The "Aquifer levels" indicator compares the current month’s figures with those of the same months in the entire record, i.e. at least 15 years of data and sometimes up to as much as 100 years of data. It is divided into 7 classes, from the lowest level (in red) to the highest (in dark blue).
The grey areas correspond to areas without unconfined aquifers, i.e. with an impermeable or semi-permeable layer above the aquifer, and/or sectors with a very low density of measuring points. This last case primarily concerns mountainous areas with small, heterogeneous aquifers.
The "Evolution of levels" indicator reflects the variation of the water level of the past month compared to the two previous months (stable, increasing or decreasing).
These global indicators reflect general situations and trends and do not take into account possible local disparities.