Drinkable water is totally a renewable resource. People have been living on the ISS for 20 years on recycled water.
There is plenty of water in the world. Water can be made drinkable by industrial processes. So, there is no risk of running out of water to drink.
However, people expect drinking water to be free, or so cheap it’s almost free. That’s not possible in some places because the water is far away or requires expensive processing to be drinkable. So, it’s not a matter of running out of water, it’s a matter of water costing more than people want to pay.
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