Map of aquifer levels in mainland France on 15 January 2026.
© BRGM
Trends observed on piezometers on 15 January 2026.
© BRGM
Trends
At 15 January, recharge was active, but slowing down, with 52% of levels up.
Rainfall in autumn and winter was generally insufficient in the Paris Basin and the eastern Artois region. Recharging has not yet become evident in the inertial aquifers in these areas. Recharging has not yet been observed in most aquifers in the centre and west of the Paris Basin. As regards the inertial aquifers of the Rhône-Saône corridor, recharging has begun and levels are rising.
For reactive aquifers, recharging depends on recent rainfall. There have been significant recharge episodes in Roussillon, Languedoc, the south of the Massif Central and Corsica, and to a lesser extent in Provence and the Côte d'Azur. Normal recharging has been observed over the central-western Aquitaine Basin. It was weak in the northern two-thirds of the country, where trends were slightly up, stable or even down. In the north, from the north of Brittany to Alsace, the rain in the first half of January was not very effective, as it first re-wet the soil after several weeks of dry weather.
Situation observed on piezometers on 15 January 2026.
© BRGM
The groundwater situation
Only the reactive aquifers in the south-east benefited from the rain that infiltrated at the end of December, and in January for Corsica, and their condition improved between the 1st and 15th January. These aquifers generally have more than enough water, with levels ranging from moderately high to very high. Some aquifer levels are still below normal, due to a chronic deficit (Roussillon), more pronounced inertia (Valras-Agde) or unevenly distributed rainfall (Bas-Rhône and Durance).
Levels remain satisfactory over a central swath, from the Aquitaine Basin to the Jura. However, the situation of many reactive aquifers is deteriorating slightly. Rainfall at the beginning of January enabled levels to be maintained for the reactive aquifers in the centre-west of the Aquitaine Basin and the centre of the Massif Central.
In the north, from the Armorican Massif to Alsace, the situation is deteriorating due to the initial, insufficient recharge. Rainfall episodes, following dry periods, were not always effective in recharging the aquifers during the autumn and early winter. The levels of the inertial aquifers in the Paris Basin and Artois remain satisfactory, ranging from moderately low to moderately high. The levels of reactive aquifers, which are sensitive to recent weather conditions, are less favourable, ranging from close to normal to low. Low to very low levels were recorded locally in northern Champagne and Lorraine.
Forecasts
The forecast for reactive aquifers remains uncertain, as they are highly dependent on rainfall infiltration in winter and spring. Forecasts are more optimistic for aquifers showing levels well above normal in December than for those whose levels are below normal. However, deficits or surpluses can be absorbed in a matter of weeks.
The forecasts at the end of winter are fairly favourable for the inertial aquifers in the Rhône-Saône corridor, even if there is still uncertainty about the end of the recharge period.
The forecast is fairly optimistic about the lack of winter drought for the inertial aquifers of the Paris Basin, where groundwater levels are currently above monthly norms. However, given the very late onset of recharge in this area, the forecast for the summer of 2026 is uncertain, particularly if the recharge is insufficient.
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 19 January 2026, based on data acquired up to 15 January 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.