Cape Town which is a major town in the country of South Africa with a population of 3 million is on the brink of running out of water in four months time if something is not done to avert Day Zero.

In Cape Town, which is located at the southwestern region of South Africa, the city is gripped by a catastrophic water crisis. Unless the city adopts widespread rationing, the government says, the taps "will be turned off" on April 22, 2018, because there will be no more water to deliver.

It’s an alarming development for a city that draws millions of tourists a year to its sandy beaches and iconic flat-topped Table Mountain which could become the first major city to run out of water.

In a bid to reduce consumption, the city has banned residents from watering their gardens and washing their cars, shut most public swimming pools and cut the water pressure, causing intermittent outages in some high-lying areas and tall apartment buildings.

Why is Cape Town running out of water?

Since 1995 the city’s population has grown 79%, from about 2.4 million to an expected 4.3 million in 2018. Over the same period, dam storage has increased by only 15%.

The Berg River Dam, which began storing water in 2007, has been Cape Town’s only significant addition to water storage infrastructure since 1995. It’s 130,000 megalitre capacity is over 14% of the 898,000 megalitres that can be held in Cape Town’s large dams. Had it not been for good water consumption management by the City, the current crisis could have hit much earlier.

Cape Town’s water system isn't built to withstand a multi-year drought which is expected to occur "perhaps as rarely as once in a millennium," according to a group of professors from the University of Cape Town.

How can 'Day Zero' be avoided?

While average daily consumption has plummeted to about 600 million liters (158 million gallons) of water a day from 1.1 billion liters a year ago, about half of households still aren't adhering to the city’s usage targets. About 19,000 homes that have regularly exceeded their recommended quotas have had mandatory devices fitted to their inlet pipes that restrict them to 350 liters a day.

Besides trying to reduce usage, the city is also rushing to augment water supply from the rain-fed dams by tapping underground aquifers, springs, and boreholes, and is fast-tracking plans to build several desalination plants.

The city can only avoid 'Day Zero' if dam levels hit 13.5% but they are currently at about 35%, down from 53% in 2016 and 92% in 2014. But contingency plans are being put in place for that eventuality. They include distributing drinking water at 200 collection points, guarded by the police and army, and rationing residents to 25 liters each.