Voters Approved 40 of 41 Ballot Measures Restricting AI Data Centers

Voters across the United States passed 40 of 41 ballot measures this week that restrict AI data centers, signaling broad public pushback against the more than 2,000 new facilities planned for communities nationwide. Water and power top the list of ratepayers' concerns. Yet calculating how much each data center draws from local resources remains an elusive task, because operators typically report usage figures companywide rather than site by site.

The stakes are concrete. Giant 1-gigawatt AI data centers from the likes of Meta, Google, Amazon and SpaceX can consume up to 10 million gallons of water per day, according to Shaolei Ren, a data center researcher and professor at the University of California, Riverside. The exact figure varies with the hardware inside a facility, its location, and the method used to cool the servers and the building as a whole. That complexity has left room for misinformation from both the builders and the projects' opponents.

Why do AI data centers need so much cooling?

Data centers need serious internal cooling to keep chips and servers from overheating. Legacy facilities, filled with lower-power servers for networking or storage, are often air-cooled: large fans move hot air away from the servers and outside the building.

Modern AI data centers are different. They are packed with high-power, denser graphics processing units, which Ren said can run so hot that the servers can "boil your eggs." Water is roughly 3,000 times more efficient at cooling these GPUs, according to Christopher Wellise, head of sustainability at Equinix.

GPUs "run at such a high wattage, a high temperature, you would need nearly hurricane-force winds to actually cool them down if you were just using air," Wellise told CNBC.

That is why the latest rack-scale AI systems — Nvidia's Vera Rubin and Advanced Micro Devices' Helios — rely on liquid cooling. Most large AI data centers use a closed-loop liquid cooling system that consumes very little water day to day.

What does 'closed-loop' actually mean for water use?

At an Equinix data center in San Jose, California, CNBC examined a closed-loop liquid cooling system serving a row of eight Nvidia Grace Blackwell racks owned by Alembic, an AI marketing startup. Equinix builds colocation data centers, where companies rent space for their own racks while Equinix supplies power, network connections, interconnectivity and cooling.

Like many operators, Equinix does not disclose water consumption at individual sites. In 2025, Equinix operations as a whole consumed 1.2 billion gallons of water, up 10% from a year earlier.

The closed loop, it turns out, is only part of the water story. Total consumption depends heavily on an additional cooling process that happens outside the data center.

"How do we reject the heat from the closed loop to the ambient environment?" Ren said. "That's where the water usage comes in."

The Meta project in Lebanon, Indiana, illustrates the gap between design claims and peak demand. Meta says the 1-gigawatt facility uses a "closed-loop, liquid-cooled system that recirculates the same water and will use zero water for a majority of the year." Yet water allocation for the site could ramp up to 8 million gallons per day by 2031, according to the company's law firm. Meta says that figure represents peak usage on the hottest days. "We anticipate rarely reaching this maximum usage level, currently projected as only a few days per year," the company told CNBC in a statement. The hottest days demand more water for the external process that removes heat from the internal closed-loop system.

How do dry and evaporative cooling trade off?

Two primary methods handle that external heat rejection: dry cooling and evaporative cooling. Dry cooling uses far less water but can require far more power, especially in hot climates where many AI data centers are being built.

"There's no sort of silver bullet," Wellise said. "At some point you need to eject that heat out to the atmosphere. And that's where those trade-offs occur."

Dry cooling relies on fans blowing air across heat exchangers. Those fans lose effectiveness when outside temperatures rise, so data centers switch on refrigeration units to pre-cool the air.

"That's a very power-intensive process, and that's exactly why we have power shortages in the summer," Ren said. "Because everybody else turns on their AC."

Evaporative cooling uses very little power. Hot water circulates through cooling towers or over wet pads exposed to air, and the portion that evaporates carries heat away. On the hottest days, large volumes of water can be lost through that evaporation.

Hybrid approaches sit between the two extremes. Equinix's San Jose site uses dry cooling in colder months and evaporative cooling when temperatures climb. In Indiana, Meta relies on dry cooling and cuts power demand in hot months by spraying a mist to cool incoming air rather than depending solely on refrigeration units.

What are companies doing about the water itself?

Near some projects, Meta, Amazon, Microsoft and others are building water treatment plants to treat and recycle what the facilities need. Meta spent $100 million on a new water and wastewater system near its data center in Kuna, Idaho.

Outside Memphis, Tennessee, Elon Musk pledged $80 million for a water recycling plant designed to convert treated municipal wastewater into cooling water for SpaceX's Colossus data centers. Colossus 1, the first data center on the site, came online rapidly in 2024, but construction on the water treatment plant was paused in April of this year.

Colossus 1 holds a water allocation of up to 1.28 million gallons per day, though it has not yet reached that threshold, according to the local utility, Memphis Light, Gas and Water.

Power generation adds its own water bill. Some companies are building their own plants on data center campuses to secure supply, and those plants consume large volumes of water as well. Colossus draws energy from gas-powered turbines installed on-site — turbines that have drawn multiple lawsuits over alleged Clean Air Act violations and noise pollution.

Can cooler chips reduce the need for cooling?

Chipmakers are attacking the problem at the source by designing silicon that generates less heat in the first place. DeepX, a South Korean startup, makes an AI processor it says runs up to 100°F cooler than competitors. Hyundai Motor will use the DeepX chip in its robotics offerings.

SK Hynix, the world's leading maker of high-bandwidth memory, told CNBC in July that it is developing a low-heat memory technology called iHBM that can reduce thermal resistance by 30%.

At Equinix, every new site undergoes a water risk analysis to determine which external cooling method to deploy in areas where water is scarce, Wellise said. He framed the wave of local ballot measures as part of a shifting public posture toward the industry.

"Communities are beginning to ask the right questions. They're concerned about water consumption," Wellise said. "We take resource consumption, resource use very seriously."

With 40 of 41 restrictive measures now passed and more than 2,000 facilities still in the pipeline, operators face a public that is demanding site-level numbers that most companies do not yet publish.