Map of aquifer levels in mainland France on 15 July 2026.
© BRGM
Trends observed on piezometers on 15 July 2026.
© BRGM
Goundwater trends
Groundwater levels continued to drop at 94% of observation points up to mid-July.
Almost all aquifers showed a marked fall in groundwater levels, due to the lack of rainfall during the second half of June and the first half of July. Soils had therefore become very dry and the little rain that actually fell – often during storms – was barely enough to meet the needs of vegetation. Moreover, increased abstraction due to higher temperatures worsened the natural decline in groundwater levels typical at this time of year.
Of groundwater levels in less-responsive aquifers, only those in the Sundgau limestone formations, remained stable. Levels dropped in the chalk aquifers of Artois and Normandy, the Paris Basin formations, the Vosgian sandstone formations and the Triassic limestone aquifers of Lorraine, as well as in the formations of the Rhône-Saône corridor, the glaciofluvial deposits of the eastern Lyon area and Savoie foreland, and the limestone aquifers of Armagnac.
Regarding aquifers with quick response times, all groundwater levels were on a downward trend, except in the alluvial aquifers of the Lower Rhône and the Durance Rivers, which remained stable.
Situation observed on piezometers on 15 July 2026.
© BRGM
Overall groundwater situation
The status of groundwater worsened in the chalk aquifer of the Artois, which has a typically low response time, with moderately low levels falling to low.
Groundwater levels in the Beauce and Armagnac limestone formations remained moderately high. Levels in the chalk aquifers of the Artois and Normandy regions, in the Paris Basin and Rhône-Saône corridor formations, and in the glaciofluvial deposits of the eastern Lyon area and Savoie foreland were close to monthly norms or moderately low. Levels were low in the Vosgian sandstones and Triassic limestone aquifers of Lorraine.
Regarding the more responsive aquifers, the situation worsened due to the lack of rainfall since mid-June and the increasing demand on water resources, caused by the needs of vegetation and human activities.
The situation changed from “close to average” to “moderately low” for groundwater levels in the limestone formations in Brie and in the Aquitaine Basin aquifers.
The state of groundwater levels also worsened, changing from “moderately low” to “low”, in the Charentes limestone aquifers, the basement aquifer of Morvan, the karst limestones of Jura, and in the alluvial formations of the Adour, Gave de Pau and Lower Garonne Rivers.
The levels in the alluvial aquifers of the Roussillon plain, the Astian sand formations in Agde as well as in the Vistrenque alluvial formations, remained moderately high to high.
Forecasts
The trend over the coming weeks is likely to continue on a predominantly downward trajectory, with Météo France forecasting hot, dry weather over the next two weeks across France.
The forecast 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. The limestone aquifers in the Boulonnais and Avesnois regions, the Vosgian sandstone formations and the Triassic limestone formations of Lorraine – whose levels are already moderately low – will need to be monitored.
Regarding responsive aquifers whose levels are currently above average, the forecast for the next few weeks is quite positive. Certain levels must continue to be monitored closely, notably in the Jurassic-arc aquifers on the north-eastern edge of the Paris Basin, in volcanic edifices, the basement aquifers in the Armorican, Limousin and Morvan regions and in the Tertiary basins of the Limagne plain. The long-term forecast is much less certain, and whether levels remain satisfactory will depend on rainfall in the coming weeks. If there is little rainfall, the growth of vegetation and an increase in abstraction could quickly have a significant impact on aquifers with very quick response times whose levels are already below average, such as the basement aquifer in the Limousin and the Triassic limestone aquifer in Lorraine.
Map drawn up by BRGM on 17 July 2026, based on data acquired up to 15 July 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.