France's groundwater levels remain deeply worrying at the start of October: two-thirds of monitoring sites are below normal and 81% are still falling. The autumn recharge, vital to rebuild reserves, has yet to get under way.
After a summer marked by exceptional drought, the situation beneath our feet remains highly worrying.
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According to the latest bulletin from the French Geological and Mining Research Bureau (BRGM), published on Thursday 8 October, 66% of groundwater monitoring points are below seasonal norms (source in French) (source in French)as of 1 October.
More importantly, the situation is continuing to deteriorate: 81% of levels are still falling, compared with only 7% that have started to rise.
After their natural decline over spring and summer, autumn rains usually begin to seep into the ground and replenish underground reserves. This year, however, the recharge has been very slow to get under way.
Why are the current rains not enough to recharge the aquifers?
For groundwater tables to refill, rainwater has to infiltrate deep into the soil. At the moment, this process is being blocked by three factors:
The prior drying of soils: after a hot, dry summer, soils are parched. The first rains are used mainly to re-moisten the surface rather than feeding underground reserves.
Evapotranspiration: under the effect of warmth and vegetation, a large part of the rainwater evaporates or is absorbed by plants before it can reach deeper layers.
The accumulated deficit: light rainfall and high temperatures at the start of the autumn season have delayed the beginning of the recharge period, which normally starts around this time.
The situation is all the more worrying as it is already clearly less favourable than a year ago. On 1 October 2025, only 31% of monitoring points were below normal, compared with 66% today. The BRGM considers the 2026 situation to be "as worrying as in 2022", even if the aquifers concerned are not exactly the same.
According to the BRGM website, in 2022 an exceptional drought, combined with scant rainfall and heavy abstraction, led to an exceptionally severe low-water situation in aquifers, with below-normal levels across much of the country.
This year the problem is also affecting so-called "inertial" aquifers, which respond slowly to changes in rainfall. Some can take months, or even longer, to recover.
By contrast, "reactive" aquifers can rise quickly after several bouts of rain. For now, though, almost all of these are still declining.
The situation is not uniform, however. Levels are very low in Limousin, Morvan, Livradois, Forez, Vivarais, and in the east, from Champagne to Lorraine via northern Alsace and as far as the Jura. Conversely, several aquifers in the south-east of the country still show more favourable levels, as this BRGM map illustrates.
Autumn will be decisive
Aquifer recharge can still begin over the coming weeks, but it will depend on regular and substantial rainfall to infiltrate the soil. A few isolated episodes will not necessarily be enough to make up the accumulated deficit.
The BRGM believes that the slowest-responding aquifers will probably continue to fall until the end of autumn. For the others, everything will depend on the rainfall still to come.
In the most depleted areas, a wetter-than-normal winter may be needed to bring levels back close to normal.
The stakes are high: groundwater supplies nearly two-thirds of drinking water and more than one-third of the water used by agriculture in France, a sector whose activity has already suffered from the 2026 drought.
Seasonal forecasts nonetheless remain uncertain. Météo-France does not yet have a sufficiently clear scenario to say whether autumn in France will be generally dry or wet.
