Strong groundwater recharge with 84% of levels rising
Rainfall in February resulted in significant aquifer recharge across the whole of France. Over three-quarters of the country in the south and west, levels were above the norm, ranging from moderately high to very high.
In the remaining northeastern quarter, groundwater levels were still moderately low but improving and following a rising trend.
The assessment of the 2025–2026 winter recharge so far suggests we can expect satisfactory levels in most of the more responsive aquifers over the next three months. However, the effectiveness of spring rainfall once the vegetation starts to grow is unknown. The outlook for the longer term remains uncertain.
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 of aquifer levels in mainland France on 1 March 2026.
© BRGM
Evolution of the trends observed on piezometers from February 2025 to February 2026.
© BRGM
Trends
The recharge period for many of the more responsive aquifers began between late August and September 2025, and paused in early October until the end of the month, before resuming into November and December. Rainfall in January was not sufficiently effective to sustain this recharge. The recharge period for the less responsive aquifers became established from October 2025 but failed to make much of an impact in most places.
In February 2026, recharge was ongoing, with 84% of levels rising compared to 56% in January. Rainfall in February resulted in exceptional aquifer recharge. This was much more intense in February 2026 than in February 2025, when only 49% of levels increased.
Inertial aquifers
Rainfall in the autumn and winter of 2025–2026 was generally less than normal in the Paris Basin and eastern Artois. In February 2026, precipitation was above normal, resulting in recharge processes extending to even the least responsive aquifers in the central part of the Paris Basin and eastern Artois, which showed a stable or rising trend in levels. Recharge processes still remained relatively slow in the central part of the Paris Basin, where rain takes longer to filter down to the groundwater.
Recharging of the less responsive aquifers of the Rhône-Saône corridor has been active since October or November 2025. In February 2026, groundwater levels were on a rising trend.
Reactive aquifers
Substantial recharge events have been observed for all of the more responsive aquifers, which are showing an upward trend. However, despite their intensity, the rainfall events were not very effective in recharging the aquifers. The impact of this rainfall on recharge depended on soil moisture, since deep infiltration is limited in dry or saturated soils. Intense precipitation over a short lapse of time often led to soil saturation, which increased runoff rather than infiltration.
Across northeastern France and the Jura, the first rains of February first wet the soils after three months of drought, before they could percolate deeper into the ground. Groundwater levels in the Jura and Lorraine Jurassic limestone responded more quickly than those in the Vosges sandstone, the Lorraine Triassic limestone and the Champagne chalk, which lagged behind.
Across the southern two-thirds of the country, Brittany and Corsica, intense precipitation events were effective in recharging the aquifers. However, saturated soils may have limited rain infiltration. At the end of February, once the rain had stopped, groundwater levels did not begin to recede very much, because of river flooding and the large amounts of water that needed to drain away.
Comparison between 1 March 2025 and 1 March 2026
Map of France showing the state of the aquifers on 1 March 2025 (left) and 1 March 2026 (right).
© BRGM
Evolution of the situation observed on piezometers from February 2025 to February 2026.
© BRGM
Aquifer situation
At the end of summer 2025, groundwater levels were generally satisfactory for the less responsive aquifers and for most of the more responsive ones. They then improved in September 2025, remained stable throughout October and December 2025, and decreased slightly in January 2026.
Groundwater levels in February 2026 were much more satisfactory than in January. They were well above normal in many places: the levels recorded in 18% of observation points were below the monthly norm, 15% were normal and 67% were above normal (compared, respectively, to 40%, 24% and 36% in January).
The current situation is comparable to that of February 2025, when 61% of levels were above the monthly norm. The situation is better in 2026 for all of the more responsive aquifers, but worse for the less responsive ones.
Inertial aquifers
The very low recharge recorded these last few months is affecting the less responsive groundwater levels in the Paris Basin and the Artois region. February rains are slowly percolating into the ground, and have not yet had an effect on the least responsive
aquifers. Groundwater levels thus remained stable or improved slightly in February 2026 for the moderately responsive aquifers on the edge of the Paris Basin. The groundwater situation was generally satisfactory, with levels close to normal, but with differences sometimes appearing within a given groundwater body. Some low levels were recorded in the northern part of the Champagne chalk.
Groundwater levels in the Sundgau (southern Alsace) and the Rhône-Saône corridor aquifers were generally close to normal. February rains were sufficiently effective to improve the levels locally.
Reactive aquifers
With regard to the more responsive aquifers in the southern two-thirds of the country, the exceptional recharge that occurred in February led to a noticeable increase in groundwater levels, which rose to moderately high to very high.
Exceptionally high levels were recorded at many observation points. Groundwater levels in Brittany, the Garonne Basin and the valleys of Garonne tributaries, the southern Massif Central, along the Mediterranean coastline and in Corsica were already above normal in January 2026. These levels remained high to very high in February. Very responsive groundwater bodies in the Jurassic and Cretaceous limestone of the northeastern part of the Aquitaine Basin improved markedly, rising to very high.
The more responsive groundwater bodies showing high levels may have contributed to river flooding in February either through groundwater emerging above the ground surface or draining into rivers, or indirectly by saturating soils, thereby reducing rain infiltration and increasing runoff. Flooding from karstic springs was also observed in places, contributing to the flooding of various rivers. Gradual groundwater drainage towards valleys probably contributed to the duration and extent of flooding.
In northeastern France, aquifer recharge was more subdued. In very responsive aquifers such as the western Lorraine and Jura limestone and in the Alsace plain, groundwater levels increased, rising to normal to moderately high. Groundwater levels in the eastern Lorraine sandstone are less responsive to rain and remained moderately low.
Aquifers with surplus water
Groundwater levels in several aquifers were very high, compared to February in previous years:
- Exceptional recharge events in February resulted in very high levels in the Jurassic and Cretaceous limestone of the northeastern Aquitaine Basin, and in the basement of the Limousin and Châtaigneraie plateau;
- Levels were exceptionally high for the alluvial aquifers of the Garonne and Dordogne rivers and their main tributaries;
- Levels in the basement of western Brittany were very high, a consequence of the large amounts of rainfall in January and February;
- Effective recharge processes from mid-December to February led to very high levels in alluvial aquifers and a number of tertiary formations along the Languedoc coastline and in Corsica, and in the southern Massif Central and Provence karst limestone.
Aquifers with low water levels
Groundwater levels in several aquifers are less satisfactory, remaining moderately low compared to those recorded for February in previous years:
- The 2025-2026 recharge for aquifers in northeastern France (Avesnois, Champagne and Lorraine) has been poor, but with groundwater levels improving, rising to normal and moderately low levels;
- The lower than normal recharge had an impact on the less responsive groundwater bodies in the Paris Basin and Artois, where levels remained close to normal;
- Rain events had little effect on the less responsive groundwater bodies in the Rhône-Saône corridor, where levels remained close to normal.
Key figures
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84.00%of levels increased
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67.00%of levels were above monthly averages
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18.00%of levels were below monthly averages
Forecasts
The Météo-France seasonal forecasts for March, April and May 2026 predict higher temperatures across the whole of France. The next three months are likely to be wetter across the northern half of mainland France. The outlook is uncertain for the southern half of the country and Corsica.
Groundwater trends and level changes over the next few weeks will depend exclusively on rainwater infiltration, which in turn depends on rainfall totals, the response times typically associated with individual groundwater bodies, and the water needs of the vegetation coming out of winter dormancy.
If Météo-France predictions hold true, spring rain in the north of the country could lead to further recharge episodes. However, the early awakening of plants due to higher temperatures could limit rain infiltration at depth. The recharge period could then end prematurely in all aquifers.
Less responsive aquifers
Groundwater levels in less responsive aquifers (Artois, Paris Basin, Sundgau and the Rhône-Saône corridor) will depend on the level reached during the previous low-water period and on effective rainfall amounts over the whole of the recharge period.
Recharging is expected to continue in March for the less responsive groundwater bodies in Sundgau (southern Alsace), and along the Rhône-Saône corridor, with the slow infiltration of February rains. The situation could then improve or remain stable, depending on the amount of rain that filters into the ground.
The end of the recharge period and the effectiveness of spring rainfall remain unknown. The outlook for the summer of 2026 is uncertain. Levels will most certainly be lower than in 2025 because of the below normal recharge of 2025-2026.
More responsive aquifers
The assessment of the 2025-2026 winter recharge so far suggests we could expect satisfactory groundwater levels in many of the more responsive aquifers over the next three months. With regard to the more responsive aquifers showing levels exceeding normal, ranging from high to very high, seasonal forecasts are optimistic. The outlook is more pessimistic for the northeastern aquifers, which showed moderately low levels in February 2026.
However, with plants starting to grow earlier than normal there is uncertainty about the effectiveness of spring rainfall, and also about overall water needs. Spring rainfall will be essential in maintaining the levels above normal for as long as possible. In the event of prolonged and intense drought, responsive aquifers can empty in a matter of weeks. The outlook for the longer term, especially for the end of summer 2026 and the low-water period, remains uncertain.
At the end of February, levels in the more responsive groundwater bodies were beginning to drop, but some across the southern two-thirds of the country, in Brittany and in Corsica remained high to very high. Groundwater flooding remains a risk, particularly if there is abundant rainfall in March. However, this risk should lessen as the discharge period approaches.
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State of groundwater: monitoring by BRGM
Groundwater is a widely used resource: in metropolitan France, it accounts for nearly two-thirds of drinking water consumption and more than one-third of agricultural water consumption. It is also widely used in the industrial sector. Groundwater tables depend on cyclical recharges.
BRGM monitors groundwater levels and quality in mainland France. Discover the actions carried out by the French geological survey and the resources and databases available on groundwater in France.
Aquifer recharge: 3 questions to provide a better understanding of the process
How do aquifers fill up and how do they empty?
Groundwater levels vary throughout the year, from high levels in winter (when vegetation does not absorb rainwater) to low levels in summer (the traditional depletion period).
The fate of rainfall varies greatly depending on the time of year and the condition of the ground surface on which it falls. Usually, the groundwater-recharge period takes place from early autumn (September-October) to early spring (March-April), a six-month period during which vegetation is dormant (with low evapotranspiration) and rainfall is generally more abundant. If the winter is dry, groundwater recharge is very low.
From spring through summer, rising temperatures coupled with the regrowth of vegetation and thus increased evapotranspiration, limit the infiltration of rainfall into aquifers. Between May and October, unless there are exceptional rainfall episodes, aquifer depletion usually continues and levels will keep decreasing until the autumn.
Why do some aquifers recharge faster than others?
Groundwater flows at different rates depending on the porosity (percentage of gaps/cracks in the rock) and permeability (capacity to allow water to circulate, i.e. interconnectivity between these gaps/cracks) of the aquifers. The larger the gaps and the more interconnected they are, the faster the water will flow, for both refilling and depletion.
It takes a given volume of water different periods of time to travel the same distance, depending on the kind of rock formation:
- a few years in a porous formation,
- a few months in a cracked formation,
- and a few days, or even a few hours, in a karst formation.
Inertial and reactive aquifers: what are they?
The impact of the winter recharge varies according to the cyclic nature of the aquifer, i.e., its reactivity to rainfall infiltration.
We refer to aquifers that are:
- reactive (when they are composed of sand, gravel, karst limestone or weathered granite formations). These aquifers are characterised by their rapid reaction times: they can recharge during heavy summer rainfall, but are also highly sensitive to drought. Their levels can therefore vary very quickly over the course of the same season.
- inertial (when composed of chalk, non-karst limestone, sandstone formations). Their reaction times are slow. They can have multi-annual cycles, meaning that they require a long period to recharge or empty.
Cyclicity of aquifers in mainland France.
© BRGM
Map drawn up by BRGM on 5 March 2026, based on data acquired up to 28 February 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.