In partnership with
Cape Town is deciding whether a data centre may be built before anyone knows how much water it will use. On 12 October the city's planning appeals panel heard the objections to a 170 MW Equinix campus near the airport. The tribunal had approved the rezoning in July, by four votes to one. Equinix, the landowner, calls the site a long-term land bank with no immediate plans. The appellants point to critical information gaps on water and electricity.
Eight years ago this city counted down to Day Zero, the day its taps would close. Here a data centre's litres are a planning question before the first rack arrives. Last week we showed Africa's operators carrying their own power. Water is the second supply they learnt to design around. The rest of a drying world is now learning it too.
Cape Town more than halved its demand and took Day Zero off the calendar
In October 2017 the mayor warned that municipal water would run out around March 2018. From 1 February 2018 residents were limited to 50 litres per person per day. Day Zero was then forecast for 21 April. Theewaterskloof, the largest dam, fell to 10 per cent full.
The city held. Demand fell 55 per cent between 2015 and 2017, without the taps being cut, by the city's own count. On 28 June 2018 the deputy mayor said the city had avoided Day Zero. Its water strategy, approved in May 2019, takes supply from four kinds of source. They are surface water, groundwater, desalination and reuse.
The appeal turns on a water design nobody has published
The applicant says water and energy details will follow in a later site development plan. So the objectors filled the gap with an assumption. The Legal Resources Centre estimated about 4.4 billion litres a year, assuming traditional cooling. That is their hypothetical worst case, not an Equinix figure. Equinix has disclosed no water design.
The case is not local. A study in Environmental Science & Technology, reported on 22 October, mapped 9,347 data centres worldwide. A quarter face a water gap for at least one month a year. The authors place the main risk on "other water users within the same basins", not the operators.
Evaporative cooling saves power and spends water, and air cooling reverses the trade
The engineering choice is a trade, not a virtue. The Lawrence Berkeley National Laboratory (LBNL) states it plainly. Evaporative systems are generally more energy efficient. Air-cooled chillers use no water but more energy. All US data centres consumed 66 billion litres directly in 2023, up from 21.2 billion in 2014.
The measure is water usage effectiveness (WUE): litres consumed per kilowatt-hour of IT electricity. The Uptime Institute's guidance is that water is local. Each site has its own water signature. In water-stressed areas, its guidance favours dry free cooling.
South Africa's operators report water use close to zero litres per kilowatt-hour
Teraco runs halls in Cape Town and Johannesburg. It says most of its facilities use closed-loop cooling designs. Its fourth sustainability report puts its 2024 use at 0.05 litres per kWh. Teraco frames these designs against water scarcity in Africa. Africa Data Centres went further when it broke ground in Nairobi, Kenya, in 2023. "We do not use water in any of our cooling systems," its chief executive said. The company also bars adiabatic systems.
Vantage's 120 MW Johannesburg campus runs air-cooled chillers on a closed loop. It expects a WUE near zero. In South Africa, Microsoft fills its cooling tanks by atmospheric water generation, drawing water from the air.
For scale, Microsoft reports a fleet average WUE of 0.30 litres per kWh. The South African figures sit far below that. Scarcity set the design rule, and the low numbers followed.
When does your project fix its water usage effectiveness?
Europe's 2026 drought brought the same constraint north, and Spain feels it first
The constraint Cape Town designed for reached Europe in 2026. World Weather Attribution found western Europe's April to June soil drought about five times more likely in today's climate. We set out its effect on river-cooled power in August.
Spain shows where the pressure lands. Objectors reported that Amazon's Aragón data centres sought 48 per cent more water, citing prolonged high temperatures. In the United Arab Emirates, Khazna's first sustainability report shows most of its 2025 cooling water was potable. Its Dubai site already cools partly on treated sewage effluent.
Spain proposes a cap of 0.1 litres per kilowatt-hour for data centres
Spain's ecological transition ministry has drafted a royal decree for data centres connected at 1 MW or more. It sets maximum values of 1.15 for power usage effectiveness (PUE) and 0.1 for WUE. They apply until an EU label, expected in 2027. Microsoft's fleet average of 0.30 would miss that ceiling threefold. Teraco's reported 2024 figure is half of it.
Cape Town is drafting its own guidelines for large data centre applications. In the United States, Tucson's council voted unanimously against Project Blue in August 2025. Water is moving from the operating permit to the planning file.
Four checks belong at siting, before the cooling is chosen
First, name the source and its backup. Cape Town now plans on surface water, groundwater, desalination and reuse together.
Second, write the design WUE into the planning file. The appeal shows the cost of leaving it to a later plan.
Third, prefer water nobody drinks. Amazon Web Services runs all its Singapore data centres on recycled NEWater.
Fourth, agree the drought plan with the basin's other users before it is needed. The mechanical engineer and the operator still choose the cooling for each site. The basin decides what that choice must survive.
The water line moves from operating cost to siting risk
For investors the change is in the schedule, not the sustainability report. An appeal over undisclosed water now stands between approval and construction in Cape Town. In Spain a draft ceiling would exclude designs that once passed easily.
The immediate priority is to read every data centre pro forma for the water behind the megawatt. Microsoft says its zero-water design avoids more than 125 million litres a year per site. It accepts a nominal increase in energy for that. That is the trade to price, site by site.
Bottom line, inherited
Cape Town once counted down to closing its taps, and it redesigned its supply. South Africa's operators built halls that barely drink. Spain now drafts the same discipline into law, and Cape Town's appellants demand it before a campus is built. Scarcity wrote the design brief first. The newly dry markets are reading it now.
Next week: Africa mines the AI century's inputs. It wants the outputs too.
Stop losing deals in between meetings.
Aligned is changing how B2B teams run their most important deals.
Most reps guess where a deal really stands. They forecast on a gut feeling and the buyer’s word vs what's actually happening. Then they realize the deal slipped through only after it's too late. Aligned surfaces what buyers are actually doing inside every deal: the risks, the openings, and the exact next step to keep things moving.
Start increasing your close rates and stand up your first deal room in minutes.