Of the 1.1 billion people without access to improved water sources worldwide, over 80% live in rural areas. Drinking-water quality is especially difficult to control, and small community water supplies frequently fail on basic microbiological quality. Rural communities have a different relationship to water than do urban dwellers. Water dominates every aspect of their lives. People in the countryside live off the land and depend on water to grow their crops. Scarce water supplies are used sparingly for household needs. Water is the source of their livelihood, and when water is unclean or mismanaged, it becomes a source of ill-health and continued poverty, thus with negative bearing on development. To achieve the international development target of halving the proportion of people without access to improved water or sanitation by 2015, an additional 1.6 billion people will require access to water supply and about 2.2 billion will require access to sanitation facilities.

Competition for water in the world’s ever-growing cities is fierce. Industry, urban agriculture and households all rely on and demand water to meet their needs. But water is becoming scarce, and this often results in the inequitable distribution of what is available. Municipal water regulations, government subsidies, public and private investment all tend to favour traditional water-supply services which provide piped .water directly into peoples’ homes, but neglect the urban poor. Hygiene practice is closely linked to the availability of water and sanitation facilities. In places where these may be lacking, communal areas which offer facilities for hand-washing, bathing and laundry may effectively encourage good hygiene. For instance, the health of communities can be enhanced if they are able to protect their water sources, dispose of solid waste and excreta, and provide wastewater drainage.

Urban habitats provide breeding grounds for diseases such as dengue fever and filaria. Control methods for reducing breeding-sites for the insect vector is a proven and effective means of cutting disease. Unfortunately, they are difficult to implement in densely-populated shanty towns with inadequate waste disposal.

Water contains many trace elements and minerals, which may be benign, beneficial or toxic. Everything depends on how much. While some minerals may be beneficial in low concentrations, most can be toxic in excess. Only a few chemicals - for instance, arsenic and fluoride - are thought to be major public health issues. The problems they and nitrate cause are most common in rural areas.

One of the worst examples of a do-good project gone wrong is occurring in Bangladesh. About two decades ago, millions of small wells began to be drilled in an effort to provide safe water to the population. At the time, all attention was focused on preventing diarrhoeal disease which ravaged the population. No one, until the 1980s, identified naturally-occurring arsenic as a health hazard. A recent study published in the Bulletin of the World Health Organization suggests that Bangladesh is grappling with the largest mass poisoning in history, potentially affecting between 35 and 77 million of the country’s 125 million population, threatening them with potential epidemics of cancers and other fatal diseases. Attacking the problem in Bangladesh is not easy. There are millions of wells and those that are dangerous are mixed in with those that are safe. There are several technical solutions but no single universal method. Well-to-well testing is needed.

Fluoride is present in all waters. Low amounts of this element can be good for teeth. But, excessive amounts of fluoride in drinking-water can be toxic. People with teeth discolored by fluoride are found worldwide, and crippling skeletal effects are prominent in at least eight countries. It is estimated that 30 million people suffer from chronic fluorosis in China where the custom of burning fluoride-rich coal in the household may further aggravate the problem. These issues can be solved and answers are available, but implementing projects, especially in the rural areas where the disease is most prevalent, have often found out to be difficult.

Of all the water-associated tropical diseases, schistosomiasis, a water-based parasitic disease, which is commonly found in some parts of Africa, the Middle East, some Caribbean islands and parts of South America best illustrates the complexities of the various water issues with which mostly the rural poor are faced. For part of their lifecycle, Schistosoma parasites depend on aquatic snails. The disease is maintained through faecal and urine contamination of open waters with parasite eggs, the presence of the snails and frequent water contact for recreational, domestic or occupational purposes.

Water management can play an important role in reducing transmission risks. But it must be combined with drug treatment, the provision of safe drinking-water and adequate sanitation. Health education is also important. Canal lining, regular rapid draw-down of reservoirs, and increased flow rates in irrigation canals all favour snail elimination, but are only efficient if they have a positive effect on agricultural production at the same time.

Contamination of traditional food sources is becoming an increasing issue of concern among indigenous populations, many of whom derive most of their drinking, irrigation and food from local lakes and rivers. In South America for example, indigenous peoples in the Andes and Amazon regions are exposed to high levels of arsenic and mercury in local water systems and fish. This is creating health problems among children and breastfed infants. For many tribal groups in Africa, unsafe drinking- water and unhygienic handling of food is contributing to high levels of diarrhoeal diseases in infants and children.

Indigenous peoples in rich countries may also live in abject poverty and suffer from the kind of ill-health and economic deprivation that are commonly found in developing countries. For example in Canada where a large indigenous population live, the statistics show that they have a lower life expectancy, higher infant mortality and greater disease burden than the rest of society. However, the outlook for disadvantaged communities in these societies is usually better because of active social support networks.

The development potential of dams includes irrigation, power generation, drinking-water supply, flood control, navigation, fisheries and recreation. Dam construction has a chequered past because of adverse environmental and health impacts.

The impacts of dams on environmental and social determinants often worsen the health status of vulnerable communities; they transfer hidden costs to the health sector and they undermine the project’s sustainability. For example, in Ethiopia the cumulative effect of microdams translated into a seven-fold increase of malaria transmission in the nearby communities.

Health impact assessment (HIA) provides a well-tested method and procedure for minimizing health risks and maximizing the health benefits of development projects. HIA fits in with prospective environmental and economic assessments. It is an effective decision-support tool, provided recommended mitigating health measures are included in the resulting environmental management and resettlement plans.

Scaling up HIA will ensure improved equity of health benefits of dams and other water-resource projects. It will prevent the transfer of hidden costs to the health sector and it will contribute a great deal to its sustainability.

The United Nations Millennium Goals aims to promote development and eliminate poverty nationally and globally. A major goal is to halve, by the year 2015, the number of people who earn less than a dollar a day, who suffer from hunger and have no access to affordable, safe drinking-water.

Providing access to better water for more than 1 billion people cannot be done overnight. Waiting for the ‘big solution’ while ignoring the immediate priorities of the most needy makes no sense. There are many small-scale, cost-effective intermediate actions which can be taken to great effect. Easy, low-cost methods for improving health do exist and can be applied collectively or individually. Water can be purified by means of chlorination and solar-thermal techniques. People can stay healthy by simply washing their hands with soap and water. Government policies can support local initiatives.

Chlorination is a proven means of ridding water of disease causing micro-organisms in piped water supply. But the prevailing wisdom is that chlorinated water should be dealt with after basic water supply and sanitation are in place.

Research carried out by scientists at the Centers for Disease Control and Prevention in Atlanta, Georgia, in the United States of America and the Pan American Health Organization looked at how chlorinated water can be provided to poor households through a simple, low-cost treatment and secure storage method. "One of the findings we’ve made is that improving water quality alone does work and we can do this without improving sanitation," says Mark Sobsey, Professor of Environmental Microbiology at the University of North Carolina, Chapel Hill, USA. "What we now know is that even in conditions of very poor sanitation and hygiene where people are collecting whatever water is available to use as household water supply, if the water is chlorinated, the water is improved microbiologically and you can find statistically significant decreases in diarrhoeal disease".

"Our research shows that washing hands with soap would probably save half of the deaths from diarrhoeal diseases," suggests Valerie Curtis, Lecturer in Hygiene Promotion at the London School of Hygiene and Tropical Medicine. "All it requires is soap and motivation." But that’s more easily said than done. Curtis participated in a major three-year study in India, the Netherlands, the United Kingdom and West Africa to learn what motivates good hygiene practices. The results are interesting and in many ways unexpected. The research finds that hygiene is a common value around the world. Nobody likes dirt. But, people’s hygienic practices have less to do with health than with social and aesthetic considerations. Mothers want to keep their babies clean because they believe it is a loving, caring thing to do and will make their babies socially acceptable. One Indian mother explains "If my child is dirty, no one will hold him in their arms, no one will love him. And, so I keep my child clean."

There has to be a rethinking of the traditional ‘scolding, moralistic’ approach to hygiene, which hasn’t worked. A number of studies show that people are turned off by dire warnings that they will face disease and death if they don’t change, "their filthy ways". For example, people in Brazil refused to collaborate in a cholera prevention program because they felt they were being accused of being ‘filthy dogs’.

Evidence is growing that positive messages are more successful than negative ones in producing behaviour change. A three-year study in Bobo-Dioulasso (Burkina Faso) used positive messages to change old entrenched habits. At the end of that period, the people in the study had tripled their use of soap. Curtis says an evaluation of the intervention shows that the money spent on the programme and buying extra soap was less than what families and health agencies had been spending on treating childhood disease. "There was actually a net saving on the overall programme."

Studies show that cases of diarrhoea were cut an average of 35% by the simple act of washing hands with soap and water. Getting people to change their habits represents a big task for health promoters.