U.S. data centers could need 697 to 1,451 million gallons of new water capacity per day by 2030 — roughly equivalent to New York City's entire daily supply. The bottleneck isn't average consumption. It's peak withdrawal. Cooling towers demand massive instantaneous flows during the hottest hours, and most municipal systems have zero surplus peak-hour capacity to spare.
The analysis (arXiv:2603.02705) reveals that efficiency gains barely dent the problem. Even with optimistic 10% annual intensity reductions, demand still reaches 227–604 million gallons per day. IT load growth — driven by AI and cloud expansion — is outpacing water efficiency improvements. The gap widens, not narrows.
The structural insight: this is a rate problem, not a volume problem. A data center that uses 2 million gallons per day averaged over 24 hours might need 300,000 gallons in a single hour. The pipe has to be that big even if the total consumption is modest. Municipal water systems are designed for residential demand patterns — morning showers, evening cooking. Data center demand is anti-correlated: hottest afternoon hours, when residential demand also peaks.
The cost of the infrastructure shortfall is $10–58 billion in new water capacity, depending on growth scenarios. This isn't a sustainability concern. It's a binding constraint. Data centers that can't get water permits can't get built. The resource that limits AI scaling might not be chips or power. It might be plumbing.