Water use, water stress and population growth

Module 1 discussed the who, how and where of water use throughout the US and the world. In the US and most industrialized countries, the dominant water uses are industry and agriculture. Domestic and municipal water use typically comprises only 15-30% of water use. In developing countries, per capita water use tends to be lower in general, with a smaller proportion dedicated to industrial use and a larger proportion dedicated to domestic uses (see Module 1, Figures 8 and 9).

It is also useful to remember that we don't actually see most of the water needed to sustain our daily activities. In the US, average per capita 'direct' use of water (domestic or municipal, for watering your yard, taking a shower, flushing the toilet, etc.) is 156 gallons per day, but the per capita 'indirect' use of water (including water used for energy production, manufacturing, food production, etc.) is 1230 gallons per day. So we really only ever see about 12% of the water that is used to sustain our quality of life. This 'invisibility' (as Charles Fishman refers to it in "The Big Thirst") of our dependency on clean, reliable water is one of the challenges in planning for the future. Often we're not even aware of what we stand to lose!

Population growth was also discussed in module 1. The population is expected to grow by nearly a third of what it is today, to around 9.6 billion by 2050. For an engaging look at population increase in real time, see the US Census Bureau Population Clock. It is all the more concerning that some of the most rapid population growth in the world (India and Africa) is expected to occur in places that are already experiencing water stress. Add to this the legacies of past policies and infrastructure as well as future projections of climate change and it seems that we have a lot of work and planning to do!