Map of aquifer levels in mainland France on 15 September 2025.
© BRGM
Trends observed on piezometers on 15 September 2025.
© BRGM
Trends
72% of levels were lower on 15 September 2025 compared with 77% at the end of August. The late August and early September rainfall managed to partially infiltrate deep into the ground and slowed depletion.
Recharge episodes were observed in reactive aquifers in the eastern half of France. The levels were stable in many aquifers along the Mediterranean, in the south of the Massif Central and in the north-eastern quarter of the country.
Levels rose in some aquifers, namely those of the Adour and Gave de Pau, the Causses du Quercy and the north-east of the Massif Central. Infiltrated rainfall compensated for the output volumes (natural outlets and abstraction).
Depletion is ongoing in areas with less rainfall and in inertial aquifers, slow to react to effective rainfall.
Situation observed on piezometers on 15 September 2025.
© BRGM
Aquifer situation
The situation remained generally stable between the reports of 1 September and 15 September. It improved for areas with reactive aquifers that benefited from heavy rainfall, these being located mainly in the eastern half of the country and the Massif Central.
The groundwater situation remains mixed, depending on the total amount of rainfall in recent weeks and the aquifer’s reactivity.
Levels are satisfactory for inertial aquifers (Paris Basin and Rhône-Saône corridor) to below normal for the less inertial aquifers in the north (Artois) and east of the Paris Basin.
The situation is generally close to normal or moderately low for reactive aquifers. Some observation points capturing the Limousin aquifer still reveal very low levels. The levels in aquifers of Roussillon and the Corbières Massif remain very unsatisfactory.
Forecasts
The recharge period could be confirmed in September in those areas that benefit from rainfall and have reactive aquifers. However, in the absence of sufficient effective rainfall, levels should continue to deplete until the arrival of heavy rains. Changes in this situation will depend on the total local rainfall.
Active depletion should continue for inertial aquifers until October-November. Their situation is not expected to change significantly. It is likely to remain stable or gradually deteriorate until the low-water point is reached, then slowly improve depending on recharge episodes.
Close monitoring should continue, in particular in the event of late low-water levels, in groundwater reserves whose levels are currently below monthly norms.
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 17 September 2025, based on data acquired up to 15 September 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.