The Meter: The Chattahoochee

The Chattahoochee River begins in a spring at the southern edge of the Blue Ridge Mountains, in the northeast corner of Georgia, and runs three hundred and thirty miles to the Florida line. Along the way it supplies drinking water to more than five million people, irrigates the farms of the Flint River basin through a shared aquifer system, and sustains one of the most productive mussel populations remaining in the southeastern United States. It is also, by volume, one of the most contested rivers in American law — the subject of a thirty-year legal dispute between Georgia, Alabama, and Florida known as the Tri-State Water Wars, a case that has reached the Supreme Court twice and is not resolved.

Into this basin, some of the largest technology companies in the world are building data centres.

Google operates a campus in Douglas County, west of Atlanta, that draws cooling water from the Chattahoochee’s tributaries. Microsoft has announced a major expansion in the same corridor. Meta’s facilities to the south depend on the same watershed. The total water permitted for data centre cooling in the greater Atlanta metropolitan area is not published as a single figure by any state agency — it is distributed across dozens of individual withdrawal permits, each granted separately, each assessed in isolation. No cumulative impact analysis exists in public record.

A data centre generates heat. Every computation — every search query, every AI inference, every cloud storage retrieval — produces thermal energy as a byproduct. That heat must be removed or the servers fail. The industry uses three primary methods to do this.

Evaporative cooling is the cheapest and most common. Water is sprayed across heat exchangers or cooling towers. The water absorbs heat and evaporates into the atmosphere. It is gone — not returned to the river, not recycled, not recoverable. A single large data centre using evaporative cooling can consume between three and five million gallons of water per day. In a drought year on the Chattahoochee, that is water that does not reach the oyster beds of Apalachicola Bay, two states downstream.

Closed-loop cooling recirculates water or a coolant fluid through sealed systems. The water is not consumed — it is reused continuously. The capital cost is higher. The water cost is a fraction of evaporative systems. Google has committed to “water-positive” operations by 2030, which includes transitioning some facilities to closed-loop or air-cooled systems. The timeline, the definition of “water-positive,” and the facility-level progress reports are not yet public in a form that permits independent verification.

Air cooling uses no water at all. It circulates ambient or chilled air over server racks. It works best in cool climates — Scandinavia, the Pacific Northwest — and less efficiently in the humid subtropical heat of Georgia, where summer temperatures routinely exceed ninety-five degrees. Air cooling in hot climates requires more electricity, which in Georgia means more natural gas combustion, which means more water consumed at the power plant. The resource cost does not disappear. It moves.

Georgia’s Environmental Protection Division issues water withdrawal permits under the state’s Water Stewardship Act. The permits are public record. The cumulative data — how much total water the technology sector withdraws from the Chattahoochee basin, and how that figure compares to agricultural, municipal, and industrial users — is not compiled or published by any state agency in a single accessible report. Researchers at Georgia Tech and Emory have attempted to aggregate the figures from individual permits. Their estimates suggest that data centre water consumption in the metro Atlanta corridor has grown by approximately four hundred percent since 2018.

Four hundred percent. In a basin where the Supreme Court has twice been asked to adjudicate how much water each state is entitled to take.

The question this column exists to ask is not whether data centres should be built. The question is whether the people who depend on the Chattahoochee — the farmers in the Flint River basin who irrigate the pecan orchards and peanut fields, the oystermen in Apalachicola Bay whose livelihood depends on freshwater flows reaching the Gulf, the five million residents of metropolitan Atlanta who drink from it every day — have the right to know, in plain and auditable terms, how much of their water is being evaporated to cool the machines that power the internet. And whether those machines could be cooled without consuming that water at all.

The technology exists. The engineering is not the obstacle.

The question is who demands it.