As residents of Cape Town, South Africa, greeted the new year, they faced a harsh ultimatum and a daunting challenge as reservoirs supplying the city’s water were going dry after a three-year drought. City officials proclaimed that soon a “Day Zero” would arrive—likely in March or April—when the city would be forced to shut off all water taps, and some 4 million residents would be forced to queue at water collection stations around the city for a ration of just 25 liters of water (6.6 gallons) per person, per day. For perspective, the average American uses about 90 gallons per day. Within a month, they got the message—that literally every drop of water counts—and the city had reduced its water usage by more than half. Day Zero was pushed back till the summer, but then the rains came and the city’s reservoirs finally filled.
