France: in mid-September 2026, 81% of groundwater levels were falling and 62% of observation points were below the monthly normal (BRGM)
On 18 September 2026 the French geological survey BRGM published the groundwater situation as of 15 September (map of 17 September, data from the national ADES database). The overall situation has stabilised, but highly reactive aquifers need attention if the lack of effective rainfall persists.
- The global indicators are built from point measurements in piezometers and show average level changes, without local disparities. The current month is compared with the same months over the whole record — at least 15 and in places more than 100 years of data — in 7 classes from lowest to highest; the trend compares the past month with the two previous months (stable, rising, falling).
- Drawdown affects the great majority of aquifers, as expected at the end of summer: soils are dry, local August rains mainly benefited vegetation and produced little effective rainfall, and thunderstorms favour runoff over infiltration; high temperatures increased abstraction. Very low levels persist among others in the basement aquifers of the Massif Central (Limousin plateau and Châtaigneraie, Morvan, Livradois, Forez, Vivarais) and the karstified limestones of the Jura.
- At the other end are very high levels in the Astian sands of Valras-Agde, high levels in the Vistrenque and moderately high levels in the coastal alluvium of the Roussillon plain and the lower Rhône with its main tributaries. BRGM expects further declines because Météo-France forecasts anticyclonic, mostly dry weather in the short term; lower abstraction for drinking water and irrigation at lower temperatures should ease the pressure.
- The national hydrological bulletin for August (OiEau, published on 18 September) reports 61% of groundwater observation points below normal, national rainfall a little more than 10% below normal and a new absolute record of the national soil drought indicator, with moisture levels lower than in mid-August 2022. As of 10 September, 93 departments had water use restrictions above the vigilance level, 74 of them at crisis level; in the same period of 2025, 78 departments had restrictions.
Source: BRGM — Nappes d’eau souterraine au 15 septembre 2026 (18.09.2026)