For the 10 years that Gabriela Verga Canovas has lived in the borough of Xochimilco on the outskirts of Mexico City she has not received a permanent water supply.
Authorities have provided only sporadic assistance to Canovas, her husband and three children, in the form of water trucks which fill 20 litre barrels near her ramshackle home on one of the poorer hillsides surrounding the city.
But the assistance has not always been forthcoming.
"For two years we have received help from the authorities. But most years I have bought it, always, always, always. I don't have money," Canovas, a 38-year-old maid, said.
The barrels' red, blue and green colours are synonymous with the homes and roadsides of many of the underprivileged neighbourhoods of the Mexican capital.
It is a puzzling problem for residents of a city the Aztecs built on five lakes and which consequently suffers annual flooding.
'Unable to wash'
"Sometimes it might come every eight days, sometimes every 15. And different amounts. Sometimes four, sometimes five barrels. Then we have to buy it," Canovas said.
"Many times I can't wash clothes, and times we can't wash ourselves. We have sometimes gone 15 days without water or help. I put aside one or two barrels that I need."
Water service cuts and rationing have been endured by millions of residents over the past year and in December 2009 the city municipality said that they would increase water tariffs for all users in 2010 and cut subsidies.
Wealthy families will reportedly pay about $40 per year under the tariffs. Those people are less likely to be without a water supply. Richer areas of the city typically have water tanks allowing them to maintain a supply during emergencies, while service cuts in poorer areas have become routine.
The issue is one which clearly highlights the inequality between rich and poor in Mexico, where despite a per capita GDP of $14,000, about 50 per cent of people live on only $4 a day.
Canovas pays about 20 pesos ($1.6) per extra barrel, which is a lot at the lower end of Mexico's income scale.
Jose Estiban Castro, the author of Water, Power and Citizenship: Social Struggle in the Basin of Mexico, said: "Certainly social inequality is at the centre of this and the rich providing for themselves and forgetting about the poorer sectors of the population."
Castro said that despite a city average of about 300 litres of water per person per day, some neighbourhoods receive hundreds of litres while others get just two or three.
Many of those without supplies do not have title deeds for their land and therefore are without a legal claim for the service.
For Castro, this situation is not adequate: "Forty or fifty litres of clean water per day per person is a human right and a right every citizen should have.
"So from that perspective, it should be immaterial if you have the title or not. The access is something that you should have because you are a human being. The state has an obligation to supply it."
A worse than expected drought last summer exacerbated the problem, bringing the Cutzamala network of reservoirs and treatment plants, from where water is pumped into the city, down to about 50 per cent of its capacity, one of the lowest levels in 15 years.
On average, it is about 70 per cent full annually.
Mexico City subsequently resorted to resources in nearby areas, such as a lake in the village of Valle de Bravo. However, this has led to depletion of water there to the point where weekenders were recently forced to navigate boats around protruding rocks due to lower lake water levels.
Yet Oscar Ibañez Hernandez, the chief of staff at Conagua, the national water commission, said that without a natural drain the city pumps out rain and wastewater instead of reusing or treating that water.
|Water trucks sporadically fill 20 litre barrels seen in poorer neighbourhoods [Rhodri Davies]
Pumping water from the aquifers causes subsidence - Mexico City is sinking at between a few inches and six feet a year depending on who you believe - leaving the ground more susceptible to flooding during the May to September rain season.
In February, communities in Mexico City and Mexico State were overwhelmed by several metres of rising water levels after heavy rains.
For daily use clean portable water is pumped from below or outside the city or delivered in trucks. Some studies estimate that about 90 per cent of the cost of water supplies is to pump water in and out of the city, costly at the capital's altitude of 7000m.
Hernandez believes that a sustainable approach would be to revert to the system of lakes used more than 500 years ago, so that that waste and rainwater is recycled.
"Instead of using the lakes and rivers of this area as sewage drains, treat and reuse that water and then allow the natural recharge of these lakes and rivers," he says.
"Have clean water coming into the area. In that regard you don't need extra pumping to get water out of the water shed."
About 10 per cent of waste water is recycled in Mexico City, compared to, for instance, 90 per cent in London.
Leakage is also a problem - the city's aging infrastructure looses about 40 per cent of the water it carries before reaching a cup.
Mexico City's residents use large amounts of water. The about 300 litres per day used compares to about 150 litres per citizen in European cities, although public education on usage is promised.
However, only about fifty per cent of what reaches a tap is metered, with many large and small quantity users not paying for the service.
A 62km-long sewage tunnel to ease flooding is planned for completion in three years, and Conagua is aiming for more small dams within the area to trap water and replenish aquifers, efficiency of water use and recycling rather that extraction.
The body has also been talking to the city government about unhindered construction that has been permitted in areas used to catch runoff water and fill aquifers, and pulled resources to their limits.
However, with coordination between city, state, and federal governments needed, and immediate political priorities of flooding and other crises, system change can be difficult to implement.
Even with political agreement it could take at least 10 years to make significant system change.
|Little waste or rainwater is recycled by the city's water system [Rhodri Davies]
With many parties only in power for six years instigating such long-term changes is difficult, although the current city government has made moves in this direction.
Mexico City's water problems are emblematic of the issues surrounding booming urban populations in many major cities such as Beijing, Jakarta and Los Angeles in the twenty-first century.
Its population has risen to 20 million, a six-fold increase over the past 50 years via migration and a high birthrate.
Hernandez said a greater understanding of water's increasing paucity is needed to ensure supplies and that to have a good service people need to pay.
"If you consume water above your basic needs everyone needs to pay for it.
"You need to have a parallel approach. You need to start charging for the water and you start improving the service."