1. Is the political will lacking?
Is the sky blue? Most governments have signed up to the millennium development goals, an ambitious set of environmental, health and education targets which include halving the proportion of people without access to safe drinking water by 2015. Last year, at the Johannesburg earth summit, they committed themselves to halving the proportion of those without sanitation by the same time. But there are few signs that governments will meet their targets. Africa alone says it needs a minimum of $6bn (£3.78bn) a year for 15. The world's richest countries face water problems themselves. The richest nine have now published their water action plan but no extra resources have been committed to water and sanitation.
2. Is more water available?
Up to a point. According to the UN, 20% of the world's population in 30 countries face severe water shortages. This number is expected to rise to 30% of the world's population in 50 countries in 2025. Meanwhile, 1 billion people do not have water within a 15-minute walk of their homes. Some regions, such as south-east Asia, have plentiful water at some times of the year and little at others. Others have little at any time. Taking more water from rivers leads to agricultural problems; taking more from underground aquifers may not be sustainable. In many areas of China and India the water table is dropping alarmingly and is not being replenished.
3. Can't water quality be improved?
It can - at a price. Unsafe drinking water is the world's No 1 killer, leading, according to the UN, to nearly 250m cases of water-related disease each year and between 5m and 10m deaths. UN figures also show that at any given time up to 50% of all people in the developing world are suffering from one or more of the six main diseases associated with water supply and sanitation - diarrhoea, ascaris, dracunculiasis, hookworm, schistosomiasis and trachoma. It's easy enough to filter water, but can be financially prohibitive on a large scale for many countries.
4. Is there a problem with the drains?
You bet. Two billion people don't have any, and nor do they have bathrooms or toilets. Bad or non-existent sanitation is the flipside of unsafe drinking water. Every year about 2.2 million people die from diarrhoeal diseases and 90% of these deaths are among children, mostly in developing countries and mostly in cities. A significant number are due to a single type of bacterium, shigella, which causes dysentery or bloody diarrhoea. It is easily controlled by improving hygiene, water supply and sanitation. Even in Mediterranean countries one in 10 hospital admissions are because of diarrhoeal diseases. The simple act of washing hands with soap and water reduces shigella and other types of diarrhoea by up to 35%. Education in this area is vital. Many cities have grown vastly in the past 20 years, filling up with people from rural areas who have never learnt about sanitation.
5. Can't countries cut pollution?
Yes. Water pollution is increasingly serious and costs a fortune to clean up. All countries have been guilty at some point of recklessly discharging municipal and industrial wastes into water courses. Microbes, salts and pollution from agriculture and industry all contribute to the problem, which is still growing in the industrialising developing countries. Ground water from underground aquifers is particularly difficult to clean up. Sometimes the problems are unforeseen: more than 100 million people in Bangladesh, India, Cambodia and Laos are likely to be affected by arsenic poisoning of ground water supplies after 10m boreholes were dug to avoid river water pollution.
6. Can we use less water?
Of course. Most of the world's fresh water is used for farming, and irrigated land provides 40% of the world's food. This will grow as populations continue to soar in poor countries over the next 40 years. Countries including Israel, the US and parts of Europe have developed drip systems which can grow plants on much less water but these are not available to developing countries. Hi-tech industries, such as computers, use excessive amounts but it is believed that new technologies could easily save at least a third of water used by industry. On a personal level, the average African family uses about five gallons (23 litres) of water a day, the average American more than 100. In industrialised countries, most people have no idea how much water they consume each day, far less how much water has been used in the processes which provide them with the goods and services they use. Cheap water saving devices can reduce household consumption. Meanwhile, if we learned not to pave over wetlands and cut down forests, we'd find that there was more water for everyone.
7. Is this about poverty?
Exactly. Poor people in south-east Asia and Africa pay an average of 12 times as much for each litre of water than those connected to municipal systems. Up to one in four of the population living in cities in developing countries must buy from vendors, typically spending 10% to 20% of their income on water. In a vicious cycle, the poor are more susceptible to ill health from water than are the well-off and so they stay poor. Meanwhile, consumerism is demanding more and more water.
8. Why not put ecology into the equation?
Ecological ignorance has led to many of the world's existing water problems. The simple fact is that taking too much water from anywhere - river, aquifer or reservoir - will inevitably lead to problems elsewhere. If you reduce river flows, food production will decline as more salt water flows upstream, or farmland will be lost. Pump too much water from below ground and the water table will drop, making it more expensive to pump up and preventing rivers from recharging. Build big dams to generate hydro-electric power and you'll displace people to the cities, deprive downstream users of valuable silt for soil regeneration, and lose up to a third of the fresh water from evaporation. Build canals to bring water efficiently to needy places and you will destroy the diversity of fish in rivers. As it is, irrigation schemes have led to the silting up of rivers and waterlogging of land and tens of millions of people have been forced into unsanitary cities by major projects. Meanwhile, cutting down forests in one place will have a direct effect on the amount of water reaching other places.
9. Can technology get us out of this hole?
Hmm. It's going to have to contribute, but there is no magic bullet. Desalination plants, once ruinously expensive, can be made far more efficient and cheap. The key is to find ways to use less. Agriculture and industry must be modernised, and people can reduce their individual needs by at least a third. The lessons are clear: mega water projects lead to as many problems as they solve and help mostly the richest, but small-scale solutions are not always effective if they are not well funded and managed.
10. Where's the money going to come from?
The UN estimates that more than $20bn a year is needed for more than a decade to provide a minimum of clean water and sanitation to the poorest. And that is just in the developing world. Thousands of cities around the world have failed to keep up with their growth and old water systems are cracking up. Up to 70% of all water and sanitation projects - large and small - fail within a few years, sometimes because there is no money to maintain them. Global bodies hope that the private sector will invest heavily, but this is politically contentious because water is seen as a public resource. Water privatisation has had a mixed record, and is beset with political and financial scandals. The public sector believes that it has the expertise, but it lacks the money. Governments of poor countries say they cannot attract global funds, yet they continue to finance huge armies, and rich countries which could easily pay for water reform are loth to invest without benefiting their own companies. Priorities are going to have to change.