STMicro's fab drinks 5 million m³ a year; the village above it gets a milk truck

Twice a week, a chrome tanker built for hauling milk climbs to Sainte-Marie-du-Mont, 1,000 metres up in the Chartreuse, to deliver 60 cubic metres a week ⁴. Three quarters of the village's supply has arrived that way since late July ⁴. Down in the valley, STMicroelectronics' site at Crolles declares a draw of a little over 5 million cubic metres of drinking water a year↗ ². The stock closed at €50.34 in Paris on 2 October, up 6.54 percent, on AI datacenter demand ¹.

Three lawmakers want a plan the state has not read

Guillaume Gontard, Jérémie Iordanoff and Cyrielle Chatelain, three green members for Isère, wrote on 24 September to the prefect and to the DREAL↗, the regional environment agency, demanding they obtain and verify the plant's water-sobriety plan ³. Their letter puts the draw at 1,000 cubic metres an hour ³.

Under drought rules in force since August, classified industrial sites holding such a plan may skip the cuts imposed on farmers and households, and ST holds one ³. The lawmakers say the document is neither public nor open to associations, and that state services appear not to know its contents ³. This summer, 84 percent of France stood in decennial drought↗ ⁴.

The defence: two basins, one budget

The communauté de communes du Grésivaudan, which runs drinking water for 43 communes and whose president is Henri Baile, answered on 2 and 3 October ². Crolles, it says, drinks from the Romanche wellfields near Grenoble, while the thirsty villages hang off Belledonne and Chartreuse springs wrecked by drought: no hydraulic link, so a cut at the fab would not fill their reservoirs ².

Then the defence's other half, in its own figures: very large industrials' bills are about half of its water-sales revenue, €10 to 12 million a year, money that paid the first €1 million phase of works keeping Sainte-Marie-du-Mont's taps on ²⁴. "The valley and the mountain are in solidarity, and that solidarity also runs through the price of water," it writes ². About 1,000 people marched against the Crolles extension in March 2025 ².

Whose word carries the water

The no-link claim is the collectivité's own, and the same authority collects about half its water-sales revenue from those same taps ². The test is not exotic: the DREAL, the regional environment agency the lawmakers copied on their 24 September letter ³, could put a hydrogeological reading under the two-basins claim the way it was asked to under the sobriety plan. Nothing published yet does either. The village's water arrives by milk truck; the fab's arrives by pipeline from another basin.

The rally prices the datacenter, not the drought

ST's June quarter brought $3.49 billion of revenue, up 26 percent↗, and $222 million of net income against a $97 million loss a year earlier ⁵. Management guided the third quarter to $3.70 billion and said the fourth will top $4 billion, "mainly driven by" AI datacenter programs, with datacenter revenue above $1 billion this year and well above $2 billion in 2027 ⁵.

The stock has climbed from a 52-week low of €18.81 to €50.34, still short of its €67.92 high↗, with a €42.2 billion market value and a print due on 21 October ¹.

What settles it

If the prefect yields the plan and it reads thin, the fight moves from letters to the expansion a thousand people marched against; if it holds up, the valley's defence holds with it ². Nothing published yet tests either question, and the 21 October call is unlikely to spend a word on water ¹. The prefect's reply, not the earnings transcript, is the document that settles this one.