For example, Australia survived its “Millennium Drought” from 1997 to 2009 by rapidly implementing measures that halved business and residential water use.

“Australia is the gold standard,” says Richard Damania, global lead economist in the World Bank’s Water Practice, and formerly of the University of Adelaide. The key was putting a price on water and making it a tradable commodity.

“[Suppose] I had water, but I’m only growing wheat. Whereas you’re growing grapes or something of higher value [than wheat, but don’t have water]” he explains. “Then I can sell you that water instead of irrigating my lower value crop. This way… Australia survived the Millennium Drought extraordinarily well.”

Another ‘gold standard’ is Israel, which views water availability as a national security issue.

By recycling effluent water, including household sewage, the Shafdan Wastewater Treatment Facility near Tel Aviv supplies approximately 140,000,000 cubic metres of water per year for agricultural use, covering 50,000 acres of irrigated land. Over 40% of Israel’s agricultural water needs are now supplied by effluent water. The waste sludge is also sent to an anaerobic digestion plant, which uses the methane as a fuel to produce renewable energy.

“If Israel can do it,” says Anders Berntell, executive director of 2030 Water Resources Group, a multi-sector water resources group, “a country located in a desert, it proves that with the right technology, economic resources and political determination, you can make it happen.”

Even more mind-blowing? Israel’s water treatment systems recapture 86% of the water that goes down the drain – the next-best performer, Spain, recycles just 19%.

Israel is also a global leader in desalination – turning seawater into potable drinking water. Over half of Israel’s drinking water now comes from desalination.

So can the world simply desalinate its way out of the freshwater crisis? It’s unlikely, says Damiane: “On average it’s about five to seven times more expensive. The energy footprint is huge, and you’ve got to do something with the salt. If you look at aerial images around the coasts of Kuwait and Dubai [areas that are highly reliant on desalination] you’ll see the havoc that is caused to marine ecosystems.” Given the costs, both economic and ecologic, “it is only a boutique solution in very rich places”, he says.

Coca-Cola say it uses desalination at around 30 coastal plants. But Greg Koch, whose title at Coca-Cola is senior director of Global Water Stewardship, explains: “We don’t see for us, nor for most places in the world, desalinisation as a solution… the capital costs are going to be higher than a treatment plant to treat freshwater.” One tactic the company uses is, where it uses desalination currently, dumping the brine out at sea via “pipes that take it away from nearshore areas”.

A simpler and cheaper solution is rainwater capture. It’s an old idea whose time may have come: Beneath Istanbul, Turkey, the Basilica Cistern built by Caesar Justinian (A.D. 527 – 565) can hold 80,000 cubic metres of rainwater. One and a half millennia on, many cities are now emulating it.

Melbourne’s largest stormwater harvesting tank can store four million litres of partially treated water. Authorities including Kerala, Bermuda and the US Virgin Islands require all new buildings to incorporate rainwater harvesting, while Singapore meets up to 30% of its water needs through rainwater capture.

Even in Manchester, England, where it rains on average 12 days every month, efforts are being made to capture the rain.

Top 18 when will earth run out of water edit by Top Q&A

Top 10+ when to use you’re

List of 10+ when can i get pfizer booster

Top 8 when will the batman be on dvd