Recently, an interesting observation from conversations with DC operators is how resilient operations have become today – two power substations, a diesel backup, three fibre routes in case one gets cut. Interestingly, that is not the case with water sourcing, even though 43% of the world’s data centres are already sitting in areas of high water stress today. Not in 2050. Today. In most cases, there is dependency on a singular water source, the municipal line.
Municipal potable water rates are up 43% over the past decade in major data centre markets. Treated wastewater costs 30-50% less. Using treated wastewater means a possibly improved COC from 2 to 6, up to 95% water recovery and a blowdown reduction of 40- 60%. These are real metrics – and they point to an efficiency and cost savings gap hiding in plain sight, in the blowdown pipe DCs are already paying to discharge.
This isn’t theoretical. At a blue-chip company’s DC in Singapore, Hydroleap’s cooling tower treatment technology delivered up to an 80% reduction in blowdown water – descaling, disinfecting (including legionella and biofilm control) and recycling the water already flowing through the system, rather than sending it down the drain.
Given the GenAI boom, quick scalability needs to go hand in hand with profitability, and a smart way for DCs to gain a strategic advantage might just be the water that’s already flowing through their systems.
Greater Resilience
Most DC teams spend considerable time meticulously tracking their PUE metrics, when in essence, the best way to optimize your PUE might just be to take WUE tracking more seriously. Roughly half of data centre operators globally don’t track water usage in any meaningful way – compared to the 82% who track power down to the kilowatt. Cooling already eats ~40% of total power draw. Yet most cooling system decisions are still made on energy and climate assumptions alone, and water gets bolted on later, when it’s too late to change the design.
When wastewater treatment technology is installed in-house, data centres can harness alternative sources: rainwater, groundwater, and treated effluent, all while saving costs. Interestingly, this reclaimed water generally has lower conductivity, which means it can be reused more times before it needs to be discarded, potentially tripling the COC in many cases.
Google already uses reclaimed or non-potable water at over 25% of its data centre campuses – including a South Carolina facility that relies on a rainwater retention pond to help cool its servers, easing pressure on a groundwater source local utilities were also fighting to protect. And yet, industry-wide, alternative sources still make up less than 5% of the average data centre’s total water supply. The tools exist. The uptake hasn’t caught up.
None of this happens by accident. Before a facility can tap rainwater, groundwater, or reclaimed effluent, someone has to map exactly where every gallon is coming from, where it’s going, and where the real opportunity for reuse sits – which is precisely the kind of water audit and balance study work Hydroleap does with operators before a single treatment system goes in.
Improved TCO
Total cost of ownership is an important KPI for any DC and the math is simple; reducing the operational costs improves the TCO.
While power, labor, equipment, and maintenance dominate the operational costs with smaller facilities, water’s clout has been increasing especially with hyperscale-level demands. More often than not, water related decisions feature too late during the design level conversations, when in fact decisions related to source supply and treatment, as well as wastewater discharge, can have a significant impact on TCO.
Improving TCO depends on a strong WUE and a that depends on pushing cycles of concentration (CoC) as high as possible. But there’s a catch: the higher you push CoC, the more concentrated the minerals in the water become, raising the risk of scaling, biofouling, and microbial growth inside the cooling tower. This is usually where most operators reach for heavier chemical dosing – but that comes with its own hidden costs.
Traditional cooling water programs often require 4-6 separate chemicals – biocides, scale inhibitors, corrosion inhibitors, pH adjusters, and dispersants – each with its own dosing schedule, storage footprint, and vendor relationship. Large facilities routinely spend $50,000-150,000+ a year just to keep this running.
And the sustainability math doesn’t work out cleanly either: heavy biocide dosing leaves cooling tower blowdown carrying high dissolved solids and residual toxic material, discharged straight into public sewers or surface waters. This means the very strategy operators reach for to protect their systems can quietly undercut the ESG story they’re trying to tell. In short, pure chemical dosing could work against the goal it was meant to support.
This is where Hydroleap technologies like EC, EO and RO can significantly reduce the contaminant build up and risk of scaling and corrosion caused by increased COC. In fact, the recovery rate of water with membrane bioreactor (MBR) and RO is as high as 85%, meaning just 15% of incoming treated wastewater needs to be discarded. This translates to significant cost savings for data centres while meeting ESG goals, which means less dependency on one source of water and more self reliance.
The ROI behind closing the loop
Ask most data centre operators about carbon credits, and they can explain the mechanism in their sleep. Ask about water credits, and most have never heard of them.
They work almost identically. One water credit represents 1,000 gallons of freshwater flow restored or improved through a verified project – funding wetland restoration, river flow recovery, or aquifer recharge. Organisations can buy them to offset their water footprint, exactly the way they buy carbon offsets today.
And the two markets are closer than they look: global water projects – from wastewater treatment upgrades to watershed restoration – could generate over 1.6 billion tonnes of CO2-equivalent in carbon credits annually. Water isn’t separate from the carbon conversation. It’s about to become one of its biggest suppliers.
Singapore’s national water agency, PUB, runs a Water Efficiency Fund that can cover up to S$5 million of the cost of a water recycling project – specifically to make the payback period faster for companies willing to invest. Practices like closed-loop cooling, wastewater recycling, and rainwater harvesting have already shown significant reductions in freshwater use elsewhere, and with funding support like this on the table, the business case gets even easier to make.
So- what’s hiding in the drain?
Not waste, but capacity that a DC might have already paid for.
Every gallon of water leaving a data centre today already went through treatment once. Sending it down the drain is essentially disposing an unclaimed asset. The operators still treating water as a third-tier concern will keep buying the same resource twice: once from the municipal line, and again in the regulatory fights, community pushback, and capacity ceilings that come from ignoring it.
Water is the one input still running without a backup plan and it’s also the one sitting on the most untapped value. Together at Hydroleap, we can make closing that gap a business case instead of just another sustainability initiative lost to the wind. This is the conversation worth having now and it might prove to be your DC’s biggest strategic advantage.
Written by Tvisha Bhanot, Market Development Intern, Hydroleap
About Tvisha:
She is currently pursuing her MSc in Management (MiM) at Singapore Management University. As a marketing professional with cross-market experience across India and Singapore, she’s experienced in brand management, digital marketing, brand communications, and consumer insights.