How Cape Town Used Behavioral Science to Beat Its Water Crisis

In March 2018, the metropolitan government of Cape Town, on South Africa’s Western Cape, announced that it had avoided “Day Zero”—the day the dams supplying the city would have reached 13.5 percent capacity, the point at which the water supply to most of the city would be turned off. Earlier in the year, the city had been forecast to hit Day Zero on April 22, 2018.

Fortunately, it didn’t come to this. The city managed to develop a successful water savings campaign which stopped the taps from running dry in Cape Town. Had this not occurred, residents would have had faced severe restrictions on water use and their daily habits would have been upended. For instance, they would have had to visit water collection sites to service their basic needs. 

The city’s bold and comprehensive communication strategy around Day Zero, which focused on changing behaviors and implementing clever nudges, was a big part of the success story. Here’s how it unfolded.

Timeline: Cape Town’s Water Crisis

Day Zero looms

In May 2017, rainfall rates in the Western Cape, where Cape Town is located, were the lowest recorded since records began in the 1880s. There was a real possibility that the Western Cape taps would run dry. 

Later that August, Cape Town’s mayor unveiled the city’s Water Resilience Plan, which detailed traditional approaches to addressing water-use behavior. It included punitive measures, such as compulsory water restriction devices for households that were not complying with restrictions, installed at the owner’s expense. A month later additional restrictions were enacted, including fines and water pressure management. But residents were still not fully complying with the pleas made by the city.

In May 2017, rainfall rates in the Western Cape, where Cape Town is located, were the lowest recorded since records began in the 1880s. There was a real possibility that the Western Cape taps would run dry. 

This lack of compliance was most likely caused by unrealistic messaging from city officials, which translated into a lack of clarity for consumers about what each restriction meant for them individually. Over the following months the city implemented increasingly drastic measures, including water rationing and fines for exceeding prescribed limits.

But by themselves fines and limits were not enough to curb people’s water use. Something fundamental had to change.

Finally, after a disappointing 2017 rainy season (generally between June and August), the city introduced its radical Day Zero campaign. The Day Zero campaign was a communications strategy which included clear messaging to residents, water saving tips, and water-use competitions. The campaign started on January 1, 2018. At that point, it was clear that if behavior did not shift, Cape Town’s taps would run out of water by April. The strategy was to use the Day Zero campaign as the countdown to when the taps were scheduled to run dry.

Cape Town’s Mayor, Patricia de Lille, issued a press statement on January 18, 2018, stating:

“It is quite unbelievable that a majority of people do not seem to care and are sending all of us headlong towards Day Zero. At this point we must assume that they will not change their behavior and that the chance of reaching Day Zero on 21 April 2018 is now very likely.”

The Day Zero Campaign: The need to change behavior

The Day Zero campaign focused on messaging and a call to action to help induce behavioral change. Three key behavioral science techniques helped reduce water consumption in Cape Town and did so quickly.

#1: Normalizing behavior change: Honest and inclusive communication

The city used its Day Zero campaign, intended to spur residents to action, to deliver a plain truth: that there was a real possibility that Cape Town’s water could effectively run out. Rarely does a government declare that a calamity is coming, for fear of being accused of bad management. But in uncertain times, it is important for institutions to be honest if they hope to be trusted.

The City made the messages easy to understand and suggested limits for water use, like showers (10 liters) and flushes (9 liters), via posters across the city (see below). Suggesting the amount of water that should be used for different activities was a key mental aid. This type of messaging provided clarity to residents and led directly to reductions in water usage.

The Day Zero campaign also put everyone in the same boat. City leaders made a deliberate effort to encourage all members of society, regardless of socioeconomic background, to change their behavior for the common good. It did not matter whether you were rich or poor; the water crisis affected you. The deputy mayor at the time said that, in the end, the people put the greater good ahead of individual luxury. He further stated that Day Zero would not have been as easily averted without this massive change in how the government approached public policy.

#2: Affirmation and recognition of good behavior: All together now!

Continuous prompts encouraged Cape Town residents. Every time consumption went down, there was collective recognition, and this helped keep up the momentum. Everyone was in it together, and everyone rejoiced and felt rewarded for the social gain.

#3: Clever nudges were devised: Making behavior change open, easy, and fun

In January 2018, the city collaborated with the Environmental Economics Policy Research Unit (EPRU) at the University of Cape Town to introduce a water map that publicly acknowledged households saving water, and to display to skeptical citizens that huge water savings were possible and being carried out by their neighbors and friends. The open and transparent tool was not meant to be a “name and shame” tool. Instead, it aimed to highlight positive behavior, a key part of the overall Day Zero ethos—be constructive to get everyone through the crisis together, not to cause fractures.

Other initiatives included two-minute shower songs and catchy slogans for toilet use such as, “If it’s yellow let it mellow” (see poster below). For instance, the shower song gave everyone a fun way to measure the amount of time they spent in the shower and create a mental cue for measuring the appropriate amount of water usage. These light-hearted initiatives were important during the crisis, because they helped to keep spirits up and infused the campaign with positivity.

Schools Smart Water Meter Competition

The Western Cape government, the Universities of Stellenbosch and Cape Town, Shoprite (a big retailer in South Africa), Cape Talk (a local radio station), and BridgIoT (internet of things solution developer) partnered to introduce water savings initiatives in schools. These activities focused on introducing behavioral interventions with smart water meter technology called Dropula, and included competitions between schools, awarding prizes to those who saved the most water. These competitions helped make water use in schools visible. The combination of raising awareness among the youth, by gamifying water reduction and working through institutions, was another example of trying to tackle the issue at a systemic level. There was a realization that this was not a one-off event and that permanent changes would require a change in mindset, especially for future generations.

Looking ahead

As we try to tackle the challenges and effects of climate change, the experience from the Western Cape offers valuable lessons. The crisis showed that the usual policy response of fines and restrictions may not be as effective at promoting behavior change as other tools, some of which we’ve outlined in this piece. The unifying factors that ultimately changed behavior in Cape Town were clear and honest messaging, a call to action for all, and a change in social norms. It was about making citizens realize that if changes in water consumption didn’t happen, the entire province would be at risk. And this change was enabled and made easy by giving continuous helpful cues and nudges that provided a constructive and fun way to make people reduce their water consumption during a perilous situation.

The unifying factors that ultimately changed behavior in Cape Town were clear and honest messaging, a call to action for all, and a change in social norms.

Looking back, the campaign helped the city change its narrative from a city in crisis to a city of resilience, which inspired everyone to come together to avoid Day Zero. This was a fundamental shift in thinking that helped motivate residents. And it looks like this motivation has continued and has helped shift residents’ perspective and relationship with water. Two years on, many residents, businesses, and governments have permanently adapted their water-saving behaviors, helping to lessen their impact on the environment.

The views represented in this article are those of the authors and do not represent their respective organizations (Western Cape Government/OECD) or constituents (OECD Member countries).

The authors would like to acknowledge the City of Cape Town, and in particular the Water and Waste Department (Sarah Rushmere, Jyothi Naidoo, Simon Maytham), WC Department of the Premier (Anthony Hazell), University of Cape Town—Environmental Policy Research Unit (Martine Visser) and University of Stellenbosch—Engineering faculty and BridgIoT (Marthinus Booysen).