Lisa Thompson. Image: SuppliedCape Town's long-term water security has once again come into focus as South Africans brace for what local media and weather experts warn could be an unusually hot and dry summer, with a powerful El Niño expected to increase the risk of below-normal rainfall, drought, and water scarcity across much of the country.
During the Day Zero crisis, Cape Town had some of the world's best scientific and engineering expertise at its disposal. There were sophisticated models, climate projections, consumption targets, dashboards and increasingly precise estimates of when the city's water system might fail. Yet despite all this knowledge, there was one thing science could not do: make the rain fall. As the crisis deepened, Capetonians turned to something completely different: people from diverse faith communities gathered to pray for rain, from mosques and synagogues to churches and large public gatherings. The significance of this is not that prayer replaced science, but that it revealed the limits of expertise. Science can help societies understand risk and prepare for uncertainty, but it cannot eliminate uncertainty. The Day Zero experience reminded us that resilience is not only about infrastructure and technology. It is also about how communities respond when confronted by the unknown.
When proposals around Cape Town's future water security were discussed at the Strand Golf Club on 5 October 2026 by the DA Mayor, Geordin Hill-Lewis, the outlook appeared reassuring. In response to questions about Cape Town's notably dry 2026 winter, it was suggested that plans were in place to manage future water scarcity. The next major additional source is expected to be the Faure New Water Scheme, supplemented by groundwater from the Cape Flats Aquifer, while large-scale desalination has effectively been pushed further down the road. Faure is expected to provide 70 million litres of purified recycled water daily in its first phase, with the first water anticipated around 2031. Desalination, once envisaged much earlier, is now expected around 2036.
I listened with a peculiar sense of déjà vu. More than twenty years ago, writing about the Berg Water Project, I examined this problem precisely: how does a water-stressed city decide when uncertainty justifies expensive new infrastructure, and who gets to define the risks on which that decision pivots? The Berg Dam was eventually built at a cost of approximately R1.5 billion, adding around 81 million cubic metres annually to the Western Cape Water Supply System. At the time, environmental organisations and civil society questioned whether another dam had become the technocratic answer to a problem that might also be addressed through demand management, recycling and alternative sources.
Underlying that debate was a debate larger than a disagreement about dams. Our work in the School of Government examined the growing "expertification" of environmental decision-making, namely, the process through which profoundly political choices about risk are translated into apparently technical questions answerable only by scientific specialists. Models are seen as indispensable, yet they also contain assumptions about rainfall, consumption, population growth, climate change and acceptable failure probabilities, as Cape Town residents have witnessed.
Yet, when science left us in the lurch, Cape Town prayed.
This was not religion operating somewhere beyond the boundaries of government. In May 2017, with dam levels at around 20 per cent, then-Mayor Patricia de Lille joined religious leaders at Table Mountain to pray for rain. On 24 March 2018, Angus Buchan's enormous “It's Time” gathering at Mitchells Plain met with a similar purpose.
This history is worth trawling through for lessons. The Cape Town government has unquestionably learned from Day Zero. Faure is the kind of alternative supply that critics of conventional augmentation argued for two decades ago. The Cape Flats Aquifer provides another buffer, along with the Berg River Voëlvlei augmentation scheme. The city is building a much more diversified water system.
But now the historical question has changed. Whilst a broad spectrum of civil society and environmental activists questioned another large dam before sufficiently exploring alternatives in the early 2000s, in 2026, the question is the reverse: do we have the “water insurance” we need? One provided by the genuinely rainfall-independent source, desalination, before another drought forces the scientific gap again?
Desalination isn’t a magic tap. It is expensive and complex. But states such as Israel show why those disadvantages have to be weighed against something far more priceless: security during prolonged hydrological stress. Israel has chosen desalination, along with wastewater reuse and conservation, for example, as have Singapore and Perth. Cape Town lags behind in that we have no desalination on standby as insurance going forward until possibly 2036, according to Hill-Lewis.
The international water security gold standard has emerged clearly since the early 2000s: not one solution but a spectrum. Dams, demand management, leakage reduction, aquifers, water reuse and desalination are combined. This means that the failure of one source does not become the failure of the entire system. Harking back to 2018, if it doesn’t rain, prayer does not need to fill the dams.
Day Zero should not be remembered as a failure of science, but as a lesson in the limits of science's control over water scarcity. The system must be resilient enough to cope with the vicissitudes of drought cycles, including the unpredictability of rainfall amid an increasingly unstable global climate.
