On 11 September 2026, Water Tech Online published a feature examining how the build-out of AI and cloud capacity is reshaping water reuse practice inside U.S. data centers, with wastewater treatment positioned as the enabling technology between stressed municipal supplies and high-density cooling loads.
Key takeaways
- More than 100 local moratoriums on data center construction have been enacted, most at city and county level, as residents push back on utility-bill increases and water stress Water Tech Online.
- A Gallup poll cited in the report found that half of Americans opposed to local data centers cite excessive water use as their concern Water Tech Online.
- Google is running its Douglas County, Georgia campus on treated wastewater from the local water and sewer authority, and Amazon Web Services has expanded reclaimed wastewater use to more than 120 U.S. sites Water Tech Online.
- OpenAI and Oracle have committed to a closed-loop cooling design for the planned Stargate hyperscale project in Michigan Water Tech Online.
- U.S. Senators Ben Ray Luján (D-N.M.) and Katie Britt (R-Ala.) introduced the Advancing Water Reuse Act in May, offering federal tax credits for on-site recycling systems and municipal water-reuse upgrades Water Tech Online.
What happened
Data centers have moved from a niche industrial water user to a focal point of community water politics, according to the Water Tech Online feature, which catalogues more than 100 local construction moratoriums and a public-opinion landscape in which half of Americans opposed to nearby data centers flag water use as their concern Water Tech Online. The outlet frames wastewater treatment as the bridge that lets operators move off potable sources, and identifies ultrafiltration (UF) membrane technology as a low-energy, space-efficient option for pretreating reclaimed wastewater and managing blowdown from evaporative cooling towers Water Tech Online.
Operators are responding in three ways visible in the report. Google is sourcing treated wastewater from Douglas County's water and sewer authority for its Georgia campus, while Amazon Web Services has expanded its reclaimed-wastewater footprint to more than 120 U.S. sites, and the OpenAI/Oracle Stargate project in Michigan has been designed around closed-loop cooling Water Tech Online. On the policy side, the May introduction of the Advancing Water Reuse Act by Senators Luján and Britt would create federal tax credits for both on-site recycling systems and municipal water-reuse upgrades Water Tech Online.
Discharge-side risk is the second pressure point. The outlet reports that blowdown carries elevated total suspended solids and accumulated scaling minerals, biocides and inhibitors, which can push municipal wastewater plants past their removal capacity and trigger higher discharge fees for the data center operator Water Tech Online. NPDES permits for surface-water discharges are state-issued and typically take 18 months or more to obtain, a timeline the outlet flags as a structural drag on the tight construction schedules typical of new builds Water Tech Online.
On the technology choice, the report cites World Economic Forum data showing closed-loop systems can cut water consumption by more than 50% compared with open evaporative cooling, at the cost of more complex piping and higher energy use Water Tech Online. The outlet notes that evaporative cooling remains preferred where power grids are constrained, while closed-loop is favoured in water-scarce basins, leaving each operator to trade water availability, electricity cost and infrastructure constraints against one another Water Tech Online.
Specification read
The Water Tech Online feature does not publish site-level flow figures for individual data centers, so a single design MLD cannot be anchored to the report. As an order-of-magnitude reference, a 100 MW hyperscale campus typically sits in the low thousands of cubic metres per day of cooling water demand (general industry range, not from the sources), and the 50%+ saving the outlet attributes to closed-loop design is the figure procurement teams should carry into evaluation Water Tech Online.
The treatment train the report points to is pretreatment-led: screening and grit removal on the reclaimed wastewater side, followed by UF for TSS and turbidity reduction, then either a closed-loop polish circuit or blowdown handling for evaporative towers, with discharge to sewer or surface water routed through whatever NPDES limits the state sets Water Tech Online. The article's central claim is that UF sits at the pinch point between reclaimed water and cooling hardware, and that the choice between evaporative and closed-loop loops back into the pretreatment spec. Buyers comparing biological trains for high-strength or surfactant-laden reclaimed sources should weigh an MBR membrane system against conventional activated sludge, since footprint and sludge yield drive site economics on tight data-center parcels. For projects that must meet a brine or zero-liquid-discharge limit on tower blowdown, the trade-off between ZLD versus high-recovery RO for data-center cooling-tower blowdown is the procurement decision that follows directly from the report's blowdown narrative.
Recognition sentence: if your plant treats reclaimed municipal wastewater or cooling-tower blowdown at a few hundred to a few thousand m³/day with elevated TSS, scaling minerals and surfactant load, and you are sizing pretreatment ahead of an evaporative or closed-loop cooling circuit under an NPDES or local discharge limit, this report marks UF as the technology the spec writer will be asked about first.
FAQ
What pretreatment is recommended for reclaimed wastewater feeding a data-center cooling loop?
The Water Tech Online feature points to ultrafiltration for TSS removal ahead of cooling hardware, with the caveat that reclaimed-water quality varies widely and may carry organics and surfactants that complicate downstream steps. Plan a jar test on the actual reclaimed source before finalising flux and backwash intervals.
How much water can a closed-loop system save versus evaporative cooling?
Citing World Economic Forum data, the Water Tech Online report puts the saving at more than 50% on water consumption, with the trade-off of higher energy use and more complex piping. Where power is cheap and water is scarce, closed-loop wins on the water ledger; where the grid is tight, evaporative still has a case.
How long does an NPDES permit typically take, and how does that hit a data-center schedule?
State-issued NPDES permits generally take 18 months or more to obtain, per the Water Tech Online report, which is a direct conflict with hyperscaler build cycles. Procurement teams should pull permit timelines into the engineering schedule at RFP stage rather than treating permitting as a parallel workstream.
Is there federal money on the table for on-site reuse right now?
The Advancing Water Reuse Act, introduced in May by Senators Luján and Britt, would create federal tax credits for on-site water recycling systems and for municipal water-recycling upgrades, according to the Water Tech Online feature. The bill is at introduction stage in the report, so treat any credit value as proposal-stage, not enacted.
