On 28 July, for the first time ever, the general assembly of the United Nations will hold a historic summit on the human right to water. It will consider and debate a resolution supporting the right to "safe and clean drinking water and sanitation" that was presented on 17 June by Pablo Solon, the Bolivian ambassador to the UN, and co-sponsored by 23 other countries. The desired outcome of the day is consensus on recognising the human right to water. However, some governments are withholding consensus and it appears likely that the resolution will have to be put to a vote, a process that has the potential to divide the world body along north/south lines.

When the 1948 universal declaration on human rights was written, no one could foresee a day when water would be a contested area. But in 2010, it is not an exaggeration to say that the lack of access to clean water is one of the greatest human rights violation in the world. Nearly 2 billion people live in water-stressed areas of the world and 3 billion have no running water within a kilometre of their homes. Every eight seconds a child dies of a waterborne disease, in every case preventable if their parents had money to pay for water. And it is getting worse as the world runs out of clean water. A new World Bank reports says that by 2030, global demand for water will exceed supply by more than 40%, a shocking prediction that foretells of terrible suffering.

For several years, international and local community groups fighting for water justice have been calling for a UN commitment that clarifies once and for all that no one should be denied water for life because of an inability to pay, especially in the light of the water markets now being set up, allowing the wealthy to appropriate dwindling water supplies for private profit. The fact that water is not now recognized as a human right has allowed decision-making over water policy to shift from the UN and governments to institutions such as the World Bank, the World Water Council and the World Trade Organisation, which favour market solutions.

Support for the human right to water has been steadily growing in recent years but several wealthy countries – notably the UK, US, Canada and Australia – have emerged as negative forces, finding excuses not to support the resolution in its current form. The new Conservative government of David Cameron is already on record that it will oppose this resolution unless it is amended to remove sanitation and only refer to "access" to clean water, not the human right to water itself. Canada hides behind the false claim that such a resolution might force it to share its water with the US; Australia has gone the route of water markets and so is unlikely to sign onto a commitment that would favour public ownership of water; and it disappointedly appears that the Obama administration is not charting a new course for his country when it comes to human rights obligations at the UN.

Nevertheless, there is great hope that 28 July will see a historic commitment of the nations of the world to once and forever recognise that every human on earth has the right to safe, clean drinking water and the dignity of good sanitation services. Will the crisis be solved the day after a successful vote on the human right to water? Of course not. The work to provide clean water in a world of diminishing supplies is just beginning.

But every now and then, humanity takes a collective step forward in its evolution. Such a time has come again and we must be up for this challenge.