In 2018, Cape Town was poised to become the first major world city to run out of water. “Day Zero” would be declared if dam levels ran down to the last 13.5%. Water to homes and businesses would be shut off and families would have to collect water rations from collection points.

“Day Zero” as it came to be called in early 2018, resulted from three consecutive dry winters (2015-17) which caused extreme drought and was a major shock to Cape Town’s socio-ecological system (Matikinca et al. 2020 in Sitas et al, 2021). The catchment areas that supply the city suffered the driest period since the 1930s making the city vulnerable because of its near-exclusive reliance on surface water.

Using a mix of price and non-price mechanisms, the city enlisted households, businesses, and citizens to respond to the drought (Matikinca et al. 2020 and Simpson et al. 2020 in Sitas et al, 2021), and the citizens responded by replacing lawns and water-sensitive plants with alternatives requiring less water, much reduced personal water use and using greywater for toilet flushing. Investments in water-saving devices such as low-flow taps, water-efficient shower heads, and smaller toilet cisterns were adopted across commercial and business sectors