Ten pots in thirty minutes: the daily struggle for water in Mumbai.

• Author: Cox, Priti Gulati

By the time the United Nations finally recognized the right to water last summer--with the General Assembly declaring "the right to safe and clean drinking water and sanitation as a human right that is essential for the full enjoyment of life and all human rights"--record numbers of people were already seeing that right fulfilled. Planet-wide, 1.8 billion more people have safe drinking water today than had it in 1990.

But that achievement, significant as it is, has barely kept up with population growth. The result, according to a recent World Health Organization/UNICEF report, is that today as in the 1970s, almost a billion people lack adequate access to water; and more than 60% of those people live in sub-Saharan Africa or South Asia.

Some negotiators had urged that the UN resolution refer only to "access to water" (translation: you can have it if you can afford it) instead of declaring an absolute right to water. Fortunately, that effort at dilution failed. Having access to water is one thing; having the source of that water reasonably close to home at a reasonable cost and obtainable with a reasonable level of effort is another.

Time and distance are at least as important as cost. According to the WHO/UNICEF report, if people face a round trip of more than 30 minutes or have to make more than one trip to collect water, they "progressively collect less water, and eventually fail to meet their families' minimum daily drinking-water needs."

Fighting for a prime-time slot

The expansion of water availability has been most successful in large urban areas of the global South. Among the beneficiaries have been the residents of Kadam Chawl ("Footsteps Slum"), a short row of tiny homes clinging to a narrow terrace on a hillside in the northern part of Mumbai, India's largest city.

One of us (Priti) spent time with the people of Kadam Chawl in late 2010; from that experience, we learned that in a city like Mumbai, where the total available water supply is barely sufficient to fill the needs of the population, a community of ordinary people won't get its fair share without first fighting for it and then working hard, day by day, to keep the flow coming.

In much of the world, extension of water supplies has been achieved by piping water directly to individual residences. But that is simply not feasible in many places with severely limited public resources. In India and the rest of South Asia in particular, water has been made more widely available primarily through community water sources. In rural areas, that has been done through village wells; in urban areas, community water taps serve the purpose.

The bulk of Kadam Chawl's water supply comes from a neighborhood tap that runs for about 20 minutes each night. It's connected to a remote branch of a labyrinthine public system that funnels water from 17 reservoirs east of the city, delivering it through almost 7000 kilometers of water mains and smaller plumbing. The sprawling system does a reasonably good job, under difficult circumstances, of providing the most important of all public services.

Kadam Chawl consists of 10 one-room, concrete-frame homes lined up along a cramped stonepathway. Near the chawl's entrance is the feature most crucial to its residents' survival: the main water tap. From there...