The former United Nations Secretary General Boutros Boutros Ghali has claimed water will be more important than oil this century. Unlike oil, it is something P&G cannot possibly live without.
And while it is naturally regenerating, the amount that P&G can use is getting smaller and being spread around more people every year.
More than 505,000 cubic kilometres of fresh water falls on the earth annually as rain or snow. But almost four fifths of this is on the oceans, and elsewhere much of it cannot be collected, leaving only about 43,600 cubic kilometres available as a resource.
Western Europe has access to only about four per cent of this and the phenomenon of climate change is expected to make the supply more difficult to guarantee over time.
A recent Friends of Europe report says: "The effect of climate change on water could result in increased demand for irrigation in agriculture, reduced hydropower potential, less available cooling water, health problems stemming from water quality and economic downturn in water-related recreation, fishing and navigation."
The report points out that warming in the Alps is already twice the world average and that as a result, runoff patterns are changing. The depth of ice on the last mountain glacier in Germany has almost halved since 1910.
Meanwhile, European lifestyles have changed significantly over the last 50 years. The fact we have water on tap means we use it everywhere: in washing machines, dishwashers, baths, showers, sinks, pools and gardens.
Consequently there is a potential risk of a growing imbalance between the supply and demand for water and a need to reduce the amount we consume or see an increasing percentage of the population experiencing water-related problems.
For the developed world, this will involve overcoming a number of water-related challenges. But the good news is that, in many cases, saving water will be as easy as turning off a tap.