The new village well in Wolisol District, Ethiopia means that Zetatute can finally attend school. She used instead to have to walk five kilometres to the river and struggle back the same distance with a pot almost as big as herself, carrying water for her family.

For Zetatute - as for millions of people across the world - the taps and piped water taken for granted in wealthier areas are just a dreamt-of luxury. Most people in poor, dry regions have no choice but to walk for hours to fetch water daily. Humans can survive for 40 days without food, but only five days without water.

Fair shares
Even though almost three quarters of the earth's surface is covered in water, only 2.5 per cent of it is freshwater - and less than a quarter of that is accessible to humans. Yet, amazingly, there still is more than enough to go around - if it were evenly distributed.

According to the United Nations, people require a minimum of 50 litres of water a day for drinking, cooking, washing and sanitation. Providing this to everyone on earth would call for only 1 per cent of the water we now use worldwide. But water is unevenly distributed, both by nature and by humankind, leaving one in six people without safe drinking water. One in three go without adequate sanitation, and 13,000 die each day from water-related disease.

Pollutants and illnesses bred in squalid conditions spread easily and threaten an already limited supply. Water sources often cross political and socio-economic lines - as do the contaminants they contain.
P. Thakur / UNEP/ Topham

Vital targets
When the world's leaders met in 2000 to set the Millennium Development Goals (MDGs), they set a target of halving the proportion of people without access to clean water. Two years later at the Johannesburg Earth Summit, they adopted the same target for basic sanitation.

Achieving these targets is vital for almost all the MDGs. Officially part of the seventh goal - ensuring environmental sustainability - they are also essential for eradicating poverty (Goal 1), improving health (Goals 4, 5 and 6), achieving universal primary education (Goal 2) and promoting gender equality (Goal 3).

Poverty cannot be beaten, nor health improved, while people go on getting sick, and dying, from unsafe water and sanitation. Fetching water keeps children from school. And the burden almost always falls hardest on women and girls.

Uneven progress
Overall the world is on track to meet the MDG drinking water target, though sub-Saharan Africa lags behind. But an estimated 2.6 billion people - half the developing world - still lack improved sanitation, 2 billion of them in rural areas. Unless there is a sharp acceleration in the rate of progress, the world will miss the sanitation target by half a billion people.

Getting clean water and even basic sanitation immensely improves a family's chances of survival. It prevents children and adults from dying of waterborne diseases such as diarrhoea and cholera. And it frees women and girls for more productive tasks, making cultivation, cooking, cleaning, and even animal husbandry, possible.