Greater Mexico City has a population of over 21 million people, and its old water pipeline wastes as much water as some of the world’s largest cities use. This briefing looks at the issues associated with water access in Mexico and what is being done about it.
Sources of Water
Mexico City is situated on an aquifer that it has been heavily exploiting with deep wells since it was found to contain potable water in 1846.⁶ The aquifer alone doesn’t provide enough water for the whole population, so other sources have been found, with water being pumped in from surrounding aquifers and even driven in by water truck, and there are still large numbers of people both in Mexico City and the rest of the country with no access to water (Box 1).
Aquifer Depletion
Nearly 70% of Mexico City’s water supply comes from the aquifer it is sat on, and extraction of water from this source is at a much higher rate than replenishment, with over-extraction of 850%,¹² which has led to drawdown of the water table of around 1m/year and subsidence of Mexico City and it’s surrounding area.¹ Average subsidence ranges from 0.1 to 1.5m/year in different areas of the capital, with heavily pumped areas undergoing a net lowering of 6 to 10m in just 6 years. Figure 1 shows the subsidence of the centre of the city since 1935, as well as in the Chalco Plain, an area where more recent ground water extraction has taken place.⁶
The Cutzamala Transfer System
The Cutzamala transfer system provides around 20% of Mexico City’s water supply.²
Water pumped in by the Cutzamala transfer system has to travel 150km and up over 1000m. Mexico City has more than 13,000km of pipes in its main and secondary network, but these are old and leaks mean that each second they lose 11 cubic meters of water, as much as some of the largest cities in the world use.³ In 2000 the Mexico City Council began a project to improve its control over water leaks and to reduce water loss in the water supply system, by splitting it up into 336 sectors. This project succeeded in reducing water losses from 35% to 23% of flow rate ³ – a significant improvement, but still a large amount of water to be losing in a city where some people do not have running water every day.
A consequence of pumping such a large amount of water over such a long distance also results in the consumption of a large amount of energy: this pumping system accounts for 0.6% of Mexico’s total energy consumption, requiring between 1.3 and 1.8 terawatt hours a year, and costing around 65 million dollars a year. The total operation costs for the entire water system is estimated to be around 135 million dollars a year. ²
Water Trucks
Some areas of Mexico City, especially rural and peri-rural areas towards the outskirts of the city, do not have any access to piped water systems, or the access they do have is incredibly unreliable. An estimated 1 million residents of Mexico City rely entirely on water trucks or similar sources for their water. In planned neighbourhoods these are subsidised by the government, whereas in unplanned neighbourhoods they are privately operated, and often the most expensive source of water, costing some people up to a tenth of their income. Often water from these trucks is higher quality than piped water in the city, however sometimes it is not safe to drink, and once delivered is carried and stored in plastic containers that most likely aren’t clean and can cause contamination even if the delivered water was clean initially.⁸
Rainwater Harvesting
Some companies, such as Isla Urbana, are trying to utilise the large amount of rainfall received by Mexico City as an alternative to using piped water. The shape of most roofs in Mexico City, combined with levels of rainfall that often lead to flooding, can combine to provide clean water to families for between 5 and 12 months of the year, as well as reducing pressure on the drainage system and aiming to allow the aquifer some time to replenish itself as there is less water from within it. With the correct care and treatment rainwater harvested from the roofs of houses can be safe to drink, and they believe that if it was implemented on a wide scale it could provide 30% of Mexico City’s water. Isla Urbana has currently installed around 3000 rainwater harvesting systems, but in a city as big as Mexico City there is still a long way to go before rainwater is a large contributor the city’s water.¹⁴
Potable Water
Mexico is the world’s largest consumer of bottled water, drinking an average of over 60 gallons per person each year, comprising 13% of the world’s total bottled water market. A big reason for this is that a large number of water systems have fallen into disrepair. An earthquake in Mexico City in 1985 broke numerous water mains, and many of the pipelines still haven’t been completely repaired – the same cracks causing water to leak out of the pipes allow contaminated water and runoff to seep into the system.⁴ In many cases, the quality of water has been improved significantly, and tap water is safe to drink, however, despite repeated assurances from the government, the culture has shifted so much that residents are unwilling to move away from bottled water back to tap water. In some cases this is due to habit or the large amount of advertising for bottled water, but in some cases the yellow or brown water they used to see coming out of their taps has lead to a permanent distrust of the water system even though the water is now perfectly clear.⁵
In 1991, a cholera outbreak prompted the
Box 2 Water Usage
According to the UN-Water Country Brief for Mexico, the country’s water usage distribution for 2009 was:
77% Agriculture
14% Municipal
5% Cooling of thermoelectric plant
4% Industrial⁹ federal government to make an investment in chlorination plants, increasing the percentage of chlorinated water from 50% to 85% within a year.¹⁵ Environment Ministry officials say that 85% of water currently in the municipal water systems is potable, however this still leaves 15% of the water dangerous to drink, and no way of knowing whether the water coming out of your tap is safe or not. Even with this figure improving, there is a large amount of distrust, with many residents simply not believing that the government can provide them with safe, clean water.⁴
Plastic Waste
One consequence of such a large amount of bottled water being consumed is the waste caused as a result. In addition to bottled water, Mexico consumes over 40 gallons per person per year of fizzy drinks, which obviously has health implications due to the large quantities of sugar, but also helps Mexico get through 21.3 million plastic bottles each day, of which only around 1/8 are recycled. The manufacturers of the bottles leave it to the consumers to recycle the bottles, but in Mexico most people simply don’t separate plastic from the rest of their waste, and those who do often struggle to find places that accept plastic for recycling.⁴
There are companies trying to change this, and one American company, Avangard Innovative Ltd., has set up a 35 million dollar recycling plant specifically to recycle PET, the most common material for drinks bottles. A large number of these are sent on to China, where they are ground into fibres, which are then used in consumer products sold to other countries including back to Mexico.
Laws and Legislations
There are several laws and legislations surrounding water in Mexico, many governing its distribution and usage¹⁰ (Box 2).
Tap Water Law
In an attempt to decrease the city’s bottled water consumption a law was passed that all restaurants must have a filter installed so that clean, free drinking water could be provided to customers without risk of stomach problems or other water-related illnesses. Failure to comply with this results in a fine.¹¹ However, drinking bottled water has become such a big part of the culture for many in Mexico City that many continue to order bottled water out of habit, or their deep-rooted mistrust of piped water. Tourists, equally, are faced with many warnings about the quality of water in Mexico, and so a large portion of the time will still opt for bottled water.
National Water Law
In 2011 the Mexican Senate included water as a basic human right in its Constitution, but they are yet to introduce a framework to protect this right, especially for people in remote rural areas who are among the most vulnerable.¹² The government has proposed a bill that would strengthen executive control over water and lead to privatisation of municipal systems, but this bill has been prevented from passing on at least three occasions by a group of citizens called National Process for Consensus on Water.
At the same time, they have put together The Citizen’s Proposed National Water Law, which would look for alternatives to privatisation and attempt to reduce the pollution caused by agricultural uses of water and reduce the demand this field puts on the country’s water supply, as well as prohibiting toxic mining and fracking using this water. The support and popularity this proposal has gathered has assisted the blocking of the government’s proposed bill. As neither bill has been passed yet, one side will need to yield or a compromise will need to be reached, but this conflict has been going on for several years and there is no sign of resolution yet.¹³