The city is building a network of desalination plants, but it is not clear when those will go into service.
Last year, the city limited residents to using 87 liters of water, about 23 gallons, per person, per day, for all uses including bathing, drinking, cooking, cleaning and toilet flushing. On Feb. 1, it lowered that limit to 50 liters, and it is fining violators.
Though consumption is down sharply, most residents have not met the 50-liter restriction, a point of tension in a city that encompasses both luxurious homes with pools and gardens, and shanty towns with communal taps.
Helen Zille, the provincial premier, has urged people to shower no more than twice a week, calling oily hair a badge of honor, and suggested reusing “gray water” from cleaning to flush toilets.
Water conservation has become the inescapable municipal calling, reinforced in the news media, public service announcements and everyday conversation. Water issues dominate the city’s website, which is topped by a link to a water use calculator to help people learn how to get under the 50-liter threshold.
For anyone accustomed to plenty, the picture is grim: Taking a two-minute shower, flushing a toilet once, washing a load of dishes, and doing ordinary drinking, cooking, cleaning and tooth-brushing is enough to reach the limit.
Even with the conservation it has achieved, Cape Town is still using about 16 percent more water than its goal of 450 million liters daily. Unless the city reaches that milestone, Day Zero might get closer, not farther away, Mr. Neilson warned.
He said, “It is imperative that we reach this target to make it through to the winter rains.”