Map of aquifer levels in mainland France on 15 June 2026.
© BRGM
Trends observed on piezometers on 15 June 2026.
© BRGM
Groundwater trends
On 15 June, the levels recorded showed that the depletion was accelerating, with a decrease noted at 86% of observation points.
A large majority of aquifers showed a marked depletion in groundwater levels, due to the lack of rainfall during the second half of May and the first half of June. The soil had therefore become extremely dry and the little rain that actually fell during this period was only beneficial to vegetation.
As regards the less responsive aquifers, stable levels were only observed in the limestone aquifers in the Sundgau region, in the fluvio-glacial formations in the eastern Lyon area and in the Savoie foothills. Levels were falling in the chalk aquifers in the Artois and Normandy regions, in the aquifers in the Paris Basin, in the sandstone formations of the Vosges and in the Triassic limestone aquifers in Lorraine, as well as in the formations of the Rhône-Saône corridor and in the limestone aquifers in the Armagnac region.
As regards responsive aquifers, the overall trend was downwards. Only the aquifers in the limestone formations of the Entre-deux-Mers region, the basement formations of the Cévennes, the Eocene sand formations of the Roussillon plain and the alluvial aquifers in the Alpine valleys had stable levels.
Situation observed on piezometers on 15 June 2026.
© BRGM
Overall groundwater situation
The situation deteriorated in two aquifers with slow response times. The levels in the aquifers in the sandstone formations of the Vosges and in the Triassic limestone formations of Lorraine fell from moderately low to low, while the level of the chalk aquifer in the Artois region also decreased from around normal to moderately low. The levels of other aquifers remained moderately low, for example the limestone aquifers in the Boulonnais and Avesnois regions, while others reached moderately high levels, for example the limestone aquifers in the Beauce or Armagnac areas.
As regards aquifers with quick response times, the situation deteriorated due to the lack of rainfall since mid-May and the increasing demand on water resources, linked to the needs of vegetation and human activities.
The situation changed from "around average" to "moderately low" in the aquifers located in the alluvial formations of the Saône, the lower Garonne, the Adour and the Gave de Pau river basins.
Similarly, the situation deteriorated in the aquifers in the Aquitaine Basin and the alluvial formations of the southern Alsace plain, which fell from "moderately high" to "around average". The level of the Limousin basement aquifer decreased from moderately low to low.
The levels of the other aquifers remained either moderately low or in line with or above monthly norms.
The levels in the alluvial aquifers of the Roussillon and Lower Rhône plains, as well as in the formations of the Vistrenque basin, remained high to very high.
Forecasts
Groundwater levels are expected to follow a predominantly declining trend in the coming weeks, according to Météo-France’s forecast of relatively dry and warm conditions for the next fortnight.
The outlook for less responsive aquifers remains uncertain. If too little rain falls, plant growth will tend to absorb it all, leaving no water to recharge the aquifers. Groundwater levels are expected to reach normal or moderately low levels in these aquifers in the coming weeks. Groundwater levels in the Boulonnais and Avesnois limestone formations are already moderately low and should be monitored closely.
The outlook is good for responsive aquifers showing levels above the norm. Groundwater sites in the arch-shaped Jurassic formations along the Paris Basin’s northeastern border, in the Vosges sandstone layers and Triassic limestone formations of Lorraine, in volcanic edifices, the Armorican and Limousin basements and the Limagne tertiary basins should be monitored closely. The long-term forecast is much less certain, and whether levels remain satisfactory will depend on rainfall in the coming weeks. Low cumulative rainfall combined with the needs of vegetation and increased abstraction could have a rapid and significant impact on the highly responsive aquifers where levels are already recorded as being below the norm, as in the Brittany and Limousin basements.
Map drawn up by BRGM on 17 June 2026, based on data acquired up to 15 June 2026.
Data source: ADES (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.