Map of aquifer levels in mainland France on 15 March 2026.
© BRGM
Trends observed on piezometers on 15 March 2026.
© BRGM
Trends
On 15 March, the recharge was still active, with 68% of levels rising.
The recharge was continuing in the vast majority of inertial aquifers. Only the limestone aquifers in the Beauce and Brie regions and those in the Armagnac region recorded levels that had either stabilised or dropped slightly. In certain local areas, notably in sectors with more reactive aquifers, some upwards trends were reversing very slowly or stabilising. This is the case in the chalk aquifers of the Artois and Champagne regions.
The trends were more variable in reactive aquifers. The recent heavy rain that fell across all of France led to exceptional recharge levels. This also increased the humidity in the ground, meaning water was more likely to filter deep down. In some areas, the depletion of the aquifers has set in and the levels have begun to drop. Falling or stable water levels were observed in the bedrock formations in Brittany, the limestone formations in Corbières, the alluvial aquifers in the Roussillon plain, the alluvial aquifers of the Hérault and Aude basins, the bedrock formations from the Cévennes to the Morvan, the volcanic formations of the Massif Central and the karst limestone aquifers in Provence. Elsewhere, the upward trends generally continued, although in some of these aquifers the trends were starting to reverse.
Situation observed on piezometers on 15 March 2026.
© BRGM
The groundwater situation
The levels of the aquifers in the Artois region, the Paris Basin, Sundgau and the Rhône-Saône corridor remained unchanged due to their typically slow response times. Their levels remained in line with average monthly norms. The sandstone aquifers in the Vosges and the carboniferous limestone aquifers in the Ardennes remained at moderately low levels, while the limestone aquifers in the Beauce and Touraine regions were at moderately high levels.
As regards the reactive aquifers, the levels observed were above average in large parts of southern and western France. The levels varied, ranging from moderately high to high. Only the aquifers in Champagne and Lorraine and those in volcanic formations had roughly average levels.
Very high levels were still being observed in the western part of the Massif Central in the karst limestone aquifers of Poitou-Charentes, the limestone aquifers of Périgord and the Angoulême area, the alluvial aquifers of the Garonne, Aude, Hérault, Rhône and Saône rivers and in the Vistrenque basin. The levels observed in the Brittany and Limousin bedrock aquifers and in the karst limestone aquifers of the Grands Causses and in Provence returned to moderately high or high levels, after the levels in reactive aquifers dropped in relation to the exceptionally high levels recorded in February.
Forecasts
The forecasts for the inertial aquifers remain uncertain. They will depend on the amount of rainfall in the spring and whether the state of the soil will allow rainwater to filter down. This is also a time when vegetation starts to regrow and consume water from the soil. Substantial rainfall will be needed to ensure that the recharge continues in these aquifers.
The forecasts for the end of winter are positive for reactive aquifers, which are above average levels. The chalk aquifer in Champagne, which has only just reached levels approaching the monthly average, still needs to be closely monitored. As with inertial aquifers, the spring rainfall will play a key role in maintaining these levels, making any long-term forecast much more uncertain. Low cumulative rainfall, combined with the resumption of vegetation growth, could have a significant impact on the highly reactive aquifers of the Brittany and Limousin bedrock aquifers.
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 18 March 2026, based on data acquired up to 15 March 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.