South Africa’s second most populous city, Cape Town, implemented a raft of water use restrictions in early 2018 that enabled it to avoid "day zero"—a complete loss of drinking water.
As a result, the city now is implementing a disaster management plan to avert a possible future day zero if dam levels drop again. The plan includes construction of desalination plants, a groundwater augmentation scheme and a water recycling plant, with a combined daily water supply capacity of 144 million liters.
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Day zero, initially predicted to come on April 12, 2018, would have seen the city of 4 million people with water taps shut off after a devastating three-year drought that nearly depleted South Africa’s entire dam storage.
A 2015-18 historic-level drought exacerbated the imbalance between water demand and the dams that supply Cape Town with water — which dipped to a low of 13.5% capacity or less in early 2018.
With an impending acute water shortage, Cape Town city authorities imposed restrictions on daily water use, limiting water to 87 liters (22.9 gallons) per person per day, which was later reduced to 50 liters (13.2 gallons).
Water tariffs were also increased to deter waste and consumption above 50 liters, while outdoor use of groundwater was banned and irrigation was severely curtailed.
Other strategies to manage daily demand included naming and shaming of the top 100 consumers that used the most water and fining those who exceeded the daily ration of 50 liters per a person.
The restriction led to a reduction in overall consumption that by early 2018 was estimated at between 510 million and 520 million liters per a day—down from the almost 1.2 billion liters daily in February 2015, according to Mmusi Maimane, former leader of South Africa's opposition Democratic Alliance political party. The reduction allowed the city to completely avoid its day zero.
Cape Town is part of the Western Cape Water Supply System of six major dams with a capacity of 900 million cubic meters, all of which rely 100% on rainfall.