Cape Town’s water crisis – the price of success

Imagine a nice autumn morning. You wake up early to go for your morning jog. It’s lovely outside, you enjoy the light breeze and you stretch it for another kilometer. You come home satisfied, sweaty and dehydrated. You open your fridge and take a sip of water, drop your clothes on the bathroom floor and walk into the shower. You open the tap and wait for the water to wash down the sweat. You wait and you wait, but not a single drop comes out of the shower head. It’s Day Zero.

To many of us, Day Zero might seem as a scene from a sci-fi movie, but on January 22, 2018 Capetonians woke up with the news that Day Zero was predicted for April 12, less than 3 months away. Day zero is the day that Cape Town’s Six Dam Reservoir system is at 13.5% storage and almost all the taps will be turned off to keep essential services and vital industry running.

The situation in Cape Town

Cape Town is South Africa’s second major city with close to 4 million inhabitants. With an average annual rainfall of only 508mm a year; warm to hot, dry summers and mild to cool, wet winters, it has a mediterranean climate. Experts predict a that climate change will lead to more frequent prolonged dry periods.

Cape Town’s water supply is almost 100% open water based. A six dam reservoir system, was built to guarantee water supply over the dry summer periods and buffer yearly variations. But at the moment, the system is near to failure. Since 2015 Cape Town is suffering from a prolonged drought. The average rainfall over the past three years has been well below the average precipitation of the past 40 years.

Screen Shot 2018-03-30 at 4.02.38 PM.png
Figure 1: Average rainfall Cape Town


Development towards the situation

Cape Town’s drought did not happen overnight. So how could it happen. Some argue that Cape Town’s population growth is to blame and that Government has not invested enough in water storage over the past 40 years. In 1971 the Voëlvlei Dam was concluded which increased the water storage capacity a sevenfold. Since then Water Storage Index, the water storage capacity per capita, has gradually fallen back from 0.52 Megaliters/person in 1980 to to 0.23 Megaliters per capita in 2016, half the 1980 value, but still double the 1970 value.

02 Water storage vs Population Growth
Figure 2: Cape Town’s population and cumulative water storage over time
03 Water storage index
Figure 3: Cape Town’s water supply index

However, Population Growth does not equal water demand growth. Since 2000, Cape Town has implemented a demand-side program that flattened the demand curve considerably, so although population growth is a factor, it seems not to explain the current water stress.

01 Graph-of-water-usage-and-population-growth.png
Figure 4: Water treated per year in Cape Town vs. population growth

Others argue that Cape Town is experiencing the worst drought in a century. But although Cape Town is experiencing a third consecutive year with a considerably lower than average precipitation, long-term rainfall data show that it is certainly not an extreme situation that should not have been taken into account in the design phase of the water supply system.

04 Rainfall data series
Figure 5: Rainfall observed over time

Data from the Six Dam Reservoir system clearly show the prolonged drought. Since 2014 the water level in the reservoir system has been on the decrease, but also show that the current situation cannot have come as a surprise to Cape Town.

Figure 6: Volume of water stored in the 6 dam reservoir system

So what has really been the root cause of Cape Town’s present ‘disaster scenario’. Ironically the success of Cape Town’s Water Demand Management/ Water Conservation(WDM/DC) program has made that investment in the water supply side have not taken place. Another important factor is that people always seem to hope that nature will come to our rescue, instead of us proactively helping nature. In May 2017 the final statement of the Western Cape Winter Rainfall Outlook Summit did not end in a consensus over the urgency of action and wrote in its final statement:


”[…] the Western Cape needs to consider the full range of possibilities which comprise that the 2017 winter season may be drier than normal […] or normal […] or wetter than normal. There is little doubt that the Western Cape needs to prepare, in the longer term, for a drier climate.” (Piotr 2018)


So the real cause of the current crisis is not population growth, drought or climate change, but the lack of courage to announce the upcoming crisis and to invest in sustainable water use and water supply.

Solutions proposed at present

Surprise or not, fact is that Cape Town needs to act to face the crisis. In an attempt to buy time and postpone Day Zero, the Council of Cape Town have implemented several measures such as rationing by decreasing water pressure, increasing water tariffs, introducing fines for households that use more water than the restricted value, 50L/person/day, and lots of advertising campaigns to convince people to reduce their water use.


”If it’s yellow let it mellow, if it’s brown flush it down.”


The Capetonians have responded well to the crisis campaigns and Day Zero has been postponed to 2019. Hopes are now set at the 2018 winter rains that are hopefully above average. Time has now become precious to workout structural measures to solve the water stress. Recently the council has presented an ambitious multi-million Rand Water Resilience Plan that aims to increase and diversify CT’s water supply through exploration of groundwater and springs, temporary water transfers between areas, and large desalination and recycling plants.

Is it enough?

Analyzing Cape Town’s Water Resilience Plan it strikes that while emergency solutions are thought on the household level and demand side, the permanent solutions are sought on a central level and supply side, that involve big engineering schemes to meet future demand. However, large environmental problems are often caused by the sum of small individual actions. Four million people using 100 liters a day sum to 400 Million liters a day. It’s true that CT’s has already a successful WDM/WC plan and its success is even considered a cause of the present crisis. Today there are more solutions on the suppy than centralized large engineering schemes.

The energy crisis is partly solved by the sum of small investments in solar power. The water crisis could follow this example. Legislation can oblige house owners to harvest rainwater. Taxation schemes could stimulate recycling of water at a household level. It is argued that these individual solutions are only available for the rich who can afford the investment. But experiences in solar energy have developed new financing solutions. The “pay-as-you-go” model allows investors to invest in (off-grid) solar panels on individual houses while the house owner or tenant pays for the energy s/he uses, on a daily or weekly basis, like it was a normal power supply system. In analogy, investors can be encouraged to invest in water harvesting and recycling systems on household level, while house owners and tenants pay in a “pay-as-you-save” model.

Large engineering works are one way of solving the problem and without doubt the most interesting way for large engineering and construction companies. However, engaging people as part of the solution by making them responsible to partly meet their own water needs, will make us all more aware and caring for nature instead of constantly hoping that nature will care for us.



Ahlfeldt C. [Internet]. 2017. Customer demand solutions & save inclusive finance can help & solve Zape Town’s drought. [updated 2017 Dec 7; cited 2018 Apr 1]. Available from:

City of Cape Town [Internet]. c2018. Cape Town, SA: City of Cape Town; [cited 2018 Apr 1]. Available from:

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City of Cape Town [Internet]. c2018. Cape Town, SA: City of Cape Town; [cited Apr 1]. Available from:

Climate Types for kids [Internet]. [cited 2018 Apr 1]. Available from:

Holder J. Kommenda N. [Internet]. 2018. How Cape Town is running out of water.; [updated 2018 Feb 3; cited 2018 Apr 1]. Available from:

Koopman M. BuysA. [Internet]. 2017. What do long-term data reveal about Cape Town’s water shortage? [updated 2017  Oct; cited 2018 Apr 1]. Available from:

Luker E. Rodina L. [Internet]. 2017. The Future of drought management for Cape Town: aummary for policy makers. Vancouver (CA):; [updated 2017 Jun 15; cited Apr 1]. Available from:

Wimberly L. [Internet]. 2017. What is government doing about Cape Town’s water crisis? [updated 2017 Jul 18; cited 2018 Apr 1]. Available from:

Wolski P. Hewitson B. Jack C. [Internet] 2018. Why Cape Town’s drought was so hard to forecast. Cape Town (SA):; [updated 2017 Oct 20; cited 2018 Apr 1]. Available from:



6 thoughts on “Cape Town’s water crisis – the price of success

  1. It’s interesting to see that even tough policies are effective, and citizens are willing to act, such a crisis can still occur; it should definitely be a lesson to everyone that we can’t rely on nature.

    You mention that Day Zero has been pushed back to next year, but I was wondering if you also know something about the recovering of the water reserves. For example, how much rain it takes for it to fill back up to the ‘normal’ or ‘secure’ level?


  2. Indeed very interesting, but also quite worrisome. I’m not sure whether you’ve checked the latest news posts with regards to Day Zero. But some argue that Day Zero will never really happen. One of them is deputy mayor Ian Neilson who claims that Cape Town will never run out of water. According to him, unnecessary panic was created over time. He mentioned that the new ‘water mechanisms’ combined with the daily restrictions would be enough to combat Day Zero. So, I’m not quite sure who or what to believe…


  3. It is very important that you point out the focus on the demand side. I think demand side management of resources is an important part of water management. At the same time, I agree that this does not seem to be suffiecient to solve the water scarcity. The reliance on surface water, e.g. reservoirs and dams, seems to be very one sided. I recently read an article mentioning the untapped potential of domestic rainwater harvesting in Cape Town. Measures like RWH could be crucial to complement other water sources. At the same time, the article assessed that it is currently not economically viable for the majority of home owners to implement RWH, so subsidies may be necessary. There is definitely no easy solution to this problem, but I believe that the set of solutions should be diverse to increase resilience. Cape Town may need to diversify its water supply to tackle this challenge in the long term.


  4. @sarahaucecs I completely agree that the set of solutions should be diverse to increase resilience: ”The energy crisis is partly solved by the sum of small investments in solar power. The water crisis could follow this example.”

    I also understand that RWH might not be economically viable for all households, however if a few hundred, or thousands of people out of the 4million Capetonians can implement RWH then that’s already better than none. Also, some Capetonians are sharing water from boreholes, and perhaps water gained from RWH could also be shared as well.


  5. @brilhodosoool I agree that a diversification even on a small scale is very important. At the same time, I think it is necessary to have a coherent multilevel governance strategy. Individual contributions are laudable, but they cannot outweigh investments made in infrastructure that might lock in entire communities dependent on one-sided water supply. Then again, pioneers are often needed before the government offers more support for others to follow, so you still have a point there.


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