I thought these days the fabs in water-scarce areas collect their waste water. re-purify it, and re-use it. So their actual drain on outside water sources is far lower.

> It will initially have a water recycling rate of around 85 percent, with a goal to achieve 90 percent. Currently, the company’s water resource center has an efficiency rate of 65 percent, converting industrial wastewater for use in the company's operations.

https://www.datacenterdynamics.com/en/news/tsmc-breaks-groun...