Clean water is essential to human health, but around the world our supplies of freshwater are increasingly threatened by pollution, overuse and climate change.

Problems with access are most severe in the developing world, where more than 5 million people perish every year from water-related diseases, and more than 1 billion people suffer without access to water for their basic needs. Even wealthy and relatively water-rich nations, like the United States, need to take action to ensure that their water supplies can meet looming threats.

Women and young girls gather around a newly built safe water point to collect water in a Kenyan village. The pumping station allows the women who operate it to avoid visiting water sources which may contain parasites. International efforts are trying to bring clean water to the nearly 1.1 billion people worldwide who lack it. Photo courtesy of WHO/TDR/Crump.

While we have the technology and a range of practical, effective approaches, substantial obstacles stand in the way of progress. International efforts to improve water access have been hobbled by a lack of funding and a focus on big, centralized infrastructure. Here in the United States, many key resources are already overstretched, and ongoing and future problems will make things worse.

With the importance of water — both at home and abroad — becoming clearer to U.S. policy-makers and political leaders, there is hope. But it cannot come fast enough to those who do not have clean water available to them.

How much is enough?

A seemingly simple water and human health question has actually engendered much debate: How much water is needed to sustain life?

The answer varies widely depending on climate and a person’s activity level and metabolism, but for most people, the absolute minimum needed to stay healthy is around 3 liters per day, or just over three-quarters of a gallon. This is, however, a bare minimum; in a hot climate, for example, people exerting themselves could consume more than 20 liters per day. These estimates do not account for cooking, washing or sanitation — nor the many other things for which we use water, such as growing food or manufacturing products.

As Peter Gleick of the Pacific Institute details in his 1996 article “Basic Water Requirements for Human Activities: Meeting Basic Needs,” published in Water International, technology exists to meet sanitation needs with no water; but because many systems still use water, it is more realistic to add an additional 25 liters per person per day for direct sanitation needs. Other studies have added 25 more liters per day for bathing and cooking.

Adding up all these estimates, we find a reasonable minimum amount of water to be 50 liters per person per day, or a little over 13 gallons. And this is similar to the figure used by the World Health Organization (WHO) for their “Basic Water Requirement.”

But of course, 50 liters per day is still only the absolute minimum needed for human health and well-being, and does not include water needed to grow food, produce energy, water landscaping or create goods. Thus, average water use in industrialized nations is far higher than this basic minimum.

In the United States, for instance, the average person uses about 380 liters per day for indoor residential use, although there is wide variation across the country. European nations tend to use less — people in the Netherlands, for example, use an average of just over 100 liters per day. Much of the variation in water use between urban areas of the United States, or between different industrial nations, boils down to how much water is for landscaping, gardens and lawns, and the efficiency of homes and businesses.

In the United States, per capita water use has been declining over the past few decades, as we continue to improve efficiency with more thrifty toilets and showers, front-loading washing machines and low-water gardens. But even though per capita use has fallen to a level not seen since the 1970s, national water efficiency and conservation efforts are unfocused and often not seen as important, especially when compared to energy.

Still, much of the water efficiency and conservation techniques and technology we have been using in the United States can be beneficial to developing nations struggling to meet their basic water needs. A simple example would be low-flush toilets and efficient showerheads. These approaches will not help the poorest people who live without plumbing, but in many areas, improving the efficiency of existing infrastructure can free up water and resources.

For those in rural areas of the developing world, technology like solar-powered water pumps, low-cost water filtration, water harvesting and simple waste disposal systems can work wonders. Organizations, including Water Partners International, Water Aid and the Pacific Institute-affiliated Water Words project, are trying to go one step further by helping affected communities develop the local know-how and resources to build and design systems tailored to their own needs, instead of just deploying systems designed elsewhere.

A global health crisis

The United States is lucky to be a relatively “water-wealthy” nation. Although some areas, such as the western states and the Southeast, have experienced severe droughts in the last few years, in general we are blessed with copious water resources aided by a vast network of dams, aqueducts and other infrastructure that brings this natural bounty into our homes and offices, factories and fields. Outbreaks of water-related disease are rare and our tap water quality is generally excellent and inexpensive.

But other nations, especially in the developing world, are not nearly as lucky or as well-equipped in terms of infrastructure or water resources. Current estimates by WHO find that roughly 1.1 billion people do not have access to clean water to meet their basic daily needs, and that 2.4 billion people don’t have adequate sanitation. These conditions lead to at least 5 million deaths every year from water-related diseases and many millions of cases of sickness and disease.

By far, the biggest killer is diarrheal diseases, which kill about 2 million people a year, according to WHO estimates. These diseases hit young children the hardest, and are the product of drinking tainted water or not having enough water for proper hygiene. Parasite-related diseases and water-related diseases like malaria (see story, page 18) and dengue fever are responsible for the balance of deaths.

Despite this grim toll, deaths tell only one piece of the story: For every person who dies, many more get sick; at least 250 million people suffer from water-related diseases each year. In turn, these cases of sickness and death take a great toll on the economy of developing nations, costing untold billions of dollars in lost economic output and diminished markets.

Regions affected by water-related disease are diverse, with deaths and illnesses in South America, Asia, India and Africa. Sub-Saharan Africa has the highest percentage of population without access to clean water, but populous nations in relatively more arid regions, like India and Bangladesh (see story, page 36), are also affected.

Attention to the critical role water plays in these regions and elsewhere arguably began in the 1970s at the United Nations-sponsored Mar Del Plata Conference and accelerated in the 1980s with the “Water Supply and Sanitation” decade. Today, this international effort continues with the “Water for Life” decade, which was launched on March 22. Due in part to these ongoing international efforts, which take the form of conferences, reports, policy directives and in-the-field projects, progress has been made in reducing the proportion of people without access to clean water.

For example, a global effort to eliminate dracunculiasis, a preventable parasitic disease more commonly known as Guinea worm disease, has also had some success. Because the parasite is transmitted via contaminated drinking water, educating people to follow simple control measures, including drinking from groundwater and filtering their water, can completely prevent illness and eliminate the disease. Such efforts have reduced the number of cases from over 3 million in the 1980s to 150,000 by 1996, and to around 75,000 in 2000, according to WHO. The disease, however, is still found among the poorest rural communities in areas without safe water supplies in sub-Saharan Africa.

In another example, a joint project between UNICEF, the government of India and local nongovernmental organizations, rural Indian villages are receiving more than 2 million hand pumps to access groundwater, instead of having to rely on often-contaminated surface water. And thousands of smaller projects have also been effective. Despite these advances, however, due to rapid population growth over the last few decades, the overall number of people without clean water continues to grow.

The United Nations has affirmed the critical role that water plays in human health in several different statements and treaties, but has taken up the more focused cause of reducing deaths from water-related diseases with the adoption of the Millennium Development Goals. These eight goals deal with pressing issues like poverty, hunger and environment. Goal seven, “Ensure environmental sustainability,” includes a target to “halve by 2015 the proportion of people without sustainable access to safe drinking water and basic sanitation.”

Even if the U.N. Millennium Goals are met, however, between 34 and 76 million people could perish from water-related diseases by 2020, according to an analysis by the Pacific Institute, making the global water crisis one of the most serious threats to human health we now face. The global water crisis is squarely on the level with other mass killers such as AIDS and heart disease.

Sadly, industrial nations spend a pittance on overseas water and sanitation projects — only five of 22 nations have met the U.N. goal for spending 0.7 percent of a nation’s gross national income on overseas development assistance, and only a fraction of all international assistance is spent on water and sanitation projects. In the period 1999 to 2001, an average of only $3 billion annually was provided for water supply and sanitation projects, but consumers are thought to spend at least $100 billion per year on bottled water (see sidebar).

Back at home

Although the developing world faces the brunt of the water-related human health crisis, the United States and many industrialized nations also face threats, albeit of a different nature.

Over the past 100 years, we have built hundreds of dams, blocking the flow of almost every major river in the United States. This development has destroyed critical habitat, decimated salmon and other fish runs and harmed users downstream. It has also pushed water resources in many places to the brink; we may be using certain supplies faster than nature can recharge them and in some places, water contamination is getting worse (see Geotimes, May 2004). To top it all off, climate change, by altering temperatures and when and where precipitation falls, may further stress water systems around the country.

We can, however, meet much of our future need through improved efficiency and intelligent planning. The Pacific Institute’s report, Waste Not, Want Not, found that California can cut its urban use by one-third using currently available water-saving technology.

New technologies and innovative planning, especially when it comes to water for agriculture, industry and energy, could yield huge further savings; we can meet our future needs, but only if we become more aggressive and organized in improving efficiency, tracking use and protecting overstressed resources. And only if we acknowledge that the global water crisis could one day come home. Bettering our situation here and overseas will require the ongoing efforts of hydrologists, geologists and other water experts, who have already given us a better picture of how the water cycle works and how to tackle both natural and human-caused change.

What we need is a new global push at the political and even societal level to help those without basic water access, so we can stem the terrible tide of death and disease that haunts the developing world. Some experts believe that $10 billion to $20 billion per year spent intelligently on community-scale efforts could make a huge improvement in the crisis over the next decade or two.

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