I lived in a town that had two lakes. No water problems for decades. Two year drought brought the lakes down about 30 feet each, so it looked a little bit like Lake Mead. Water rationing in the second year, maybe the tail end of the first, I no longer recall. Brown lawns everywhere

The city finally got permission from the state and the Army Corps to divert water from a nearby river, but only when the river was at a relatively high rate of flow. So functionally what happened was that once the drought broke they were able to refill the lakes faster, and top them up during storms in wet/dry cycles.

Every place is going to have higher and higher odds of becoming water-stressed over the next three decades. Some places more than others. Will the data centers shut down in those situations?

You might think that using 5% of the municipal water supply isn't much but it's a significant fraction of what austerity measures would be able to conserve to retain water through a prolonged drought. In that situation holding water a few extra months until the rains return is the goal.