Other hotels I checked with had similar restrictions, though like mine, their shower limits were based on the honor system, not automatic shutoffs. One still had a functioning heated pool. Tourism brings the province more than $3 billion a year, and it seems they can’t risk losing it.

That night at dinner, a restaurant’s menu declared that to “mitigate the impact our industry has on the available water supply,” it would be offering bottled water to its customers, rather than a customary glass of tap. I ordered a carafe of local wine for 30 rand, or about $2.50, thinking it would help save water. It was not, it turns out, an environmentally friendly choice: It takes 34 gallons of water to produce 5 ounces of wine. The area’s agricultural sector, which is already expecting its smallest wine harvest in a decade, was recently ordered to reduce its water use by 60 percent.

The next day, I decided to go see what’s happening at the place that’s practically an ode to water: the Kirstenbosch National Botanical Garden, a 1,300-acre, indigenous-plant-filled park that rambles up the side of Table Mountain. Here, yet another a sign admitted the garden was running its sprinklers less often and offered some general water-saving tips, including the apparently internationally understood dictum “If it’s yellow, let it mellow.” Some of the plants had wilted under the bright sun. But the native fynbos flowers, perhaps accustomed to climactic deprivations, looked bright and perky as ever. In the bathroom, a little girl delicately dispensed a few drops from the faucet onto her hands as her mother, watching, whispered, “We must save water.”

It didn’t really hit me until I visited the local supermarket, Checkers, where I was confronted by an empty shelf where the bottled water should be. Yet another sign said water purchases would be limited to 20 liters per person.

In interviewing a half-dozen people outside the market, I got a sense of who Day Zero would really devastate: the locals, especially those who can’t afford to get away.

People said that for months, they have been showering into a bucket, then using that water for their gardens. They’ve drilled boreholes. Water left over from washing clothes is collected and used to flush the toilet—and then, only when it’s, uh, brown. They’re allowed 50 liters per person per day—less than a bathtub’s worth—and risk fines if they exceed the limit. The average American, by contrast, uses 370 liters a day.

Sarka Svoboda said she wears clothes till they’re visibly dirty. It rained a little recently, and she regretted forgetting to set buckets out to catch the water.

She fished a spray bottle out of her blue Checkers bag. It’s a substance meant for spritzing on pee to make it smell less while it’s “mellowing” in the toilet bowl. She’s already bought the 25-liter bucket she will use to collect her water ration if Day Zero comes, along with the 5-liter garden sprayer she will use to shower.