France’s drought deepens as heatwave strains water supplies and power output

France is entering a more severe phase of early-summer drought as a strong heatwave combines with a sharp rainfall deficit, deepening pressure on rivers, groundwater and electricity production.

Restrictions or water-saving appeals are now in place in 78 prefectures across mainland France, according to reporting published June 25. In about 15 administrative departments, emergency measures are already stricter, including bans on irrigating crops from rivers in parts of central France since June 23.

The worsening conditions are being driven by both heat and lack of rain. France recorded its hottest day ever on June 24, and officials say the same weather pattern is accelerating evaporation, drying soils and heating waterways at the same time that demand for water is rising.

Groundwater and rainfall

The official groundwater bulletin from BRGM, published June 19 using data from June 15, said 86% of monitored groundwater levels were falling. BRGM described the overall national situation as moderately satisfactory, but said the trend was expected to remain mostly downward if effective rainfall stays scarce.

The bulletin also showed that the picture is not uniformly bleak. BRGM said 55% of monitoring points were around or above monthly norms as of June 15, even as the broader direction across the network was downward.

Le Monde reported that rainfall since the start of June averaged 27 mm nationwide, compared with a June normal of 68 mm. It said soils were already parched, with conditions worsening in Alsace and Aquitaine and likely to deteriorate at least through the end of the week.

That combination of weak rainfall, drying soils and falling groundwater is what is turning a hot spell into a broader water-supply problem. The risk is not only on farms, but also for drinking-water systems, river ecosystems and the infrastructure that depends on stable river flows.

Power generation under pressure

EDF has already had to adjust nuclear output because of river temperatures. The company said Golfech Unit 2 was shut down at 23:45 on June 22 after forecasts showed the Garonne was expected to reach 28C on June 23, close enough to the regulatory limit to require action.

EDF said the shutdown was taken to comply with the 18 September 2006 regulation governing river-temperature limits. The company also said Golfech’s water discharge is normally about 0.2C warmer on average, underscoring how little margin exists when rivers heat up during a drought.

Le Monde reported earlier that elevated river temperatures were already creating uncertainty for several EDF reactors, while RTE said the wider grid remained secure. The issue is not a system-wide shortage of electricity, but the loss of flexibility when river-cooled plants must reduce output to protect waterways.

Rivers, dams and ecosystems

Low river levels are also affecting hydropower management. Le Monde reported that hydroelectric dams in the Pyrenees will need to release water earlier than usual to keep the Garonne from running dry.

Franck Solacroup of the Garonne Gascogne and Pyrenees Tributaries Public Establishment said that in 33 years of low-water support, releases had never been needed this early. That makes the current drought notable not just for its intensity, but for its timing.

Warmer rivers are also a direct ecological stress. The reporting cited river heating as a problem for ecosystems, where lower flows and higher temperatures can reduce dissolved oxygen and leave aquatic life more vulnerable.

The Seine offers another sign of the heat’s reach. Le Monde reported that the river averaged 26C in Rouen on June 23, exceeding the previous 2025 peak.

What officials are watching

The key near-term question is whether more prefectures will move from conservation appeals to mandatory restrictions, or whether existing limits will tighten if rainfall stays weak.

BRGM’s next groundwater updates will show whether the downward trend begins to stabilize. For now, the official bulletin points in the opposite direction, with most monitored levels still falling and little evidence yet of sustained recovery.

Authorities are also watching for additional operational changes from EDF and other river-cooled facilities if temperatures remain high. The June 22 shutdown at Golfech shows that the drought is already affecting industrial and power-sector decisions, not just agriculture.

Hydropower managers, prefectures and water agencies will be tracking the same signals: rainfall, soil moisture, groundwater and river temperature. If the heat persists, the pressure on all four is likely to intensify.

For households, farmers and local officials, the immediate picture is one of rising constraint. More people are being asked to use less water, more waterways are running hot, and the systems that depend on those rivers are being forced to adapt in real time.