Groundwaters in Mexico. Situation, Challenges and Opportunities

Water is not the only component of wellbeing or sustainability, but there is no doubt that without water no well-being nor sustainability is possible. Well-being of those who make up today’s society matters a lot; as much as that of those who will be incorporated with the passage of time, and along with them will come the articulation of decisions, omissions, and institutional events already underway. For this reason, it is important to consider what are the sources of present and future well-being, their gaps and regional and national changes, as well as what opportunities we should take advantage of to maintain or increase it, and what inertias and unfavorable actions we should avoid so as not to lose it irretrievably. Losing social welfare, eroding its sources, and widening the gaps of inequality and exclusion represent undesirable and very costly situations that carry multiple and additional adverse consequences. Precarious coverage in health, education, food, housing, formal employment, real income, public security, or water, among other irreplaceable components, make it impossible to affirm that today we have generalized social welfare or that we incontrovertibly tend towards the environmental sustainability of economic and social development.

This article addresses those sources of well-being that directly come from having access to water in sufficient quantity, with adequate quality, in acceptable and affordable conditions, as well as those that derive from having hydrological systems in good conditions, available water flows, and a hydraulic infrastructure that operates regularly and efficiently the supply of water for different uses and users. Overall, access to and use of flows allows us to satisfy basic needs such as hydration, hygiene, metabolism, health, sanitary management, food preparation, agricultural, agro-industrial and manufacturing production, energy generation, supply of services, and conservation of ecological collections and hydrological flows in basins, aquifers, regions, municipalities and cities. Therefore, having access to the volumes of water needed daily and having the natural systems conserved and the hydraulic infrastructure functioning is essential for our lasting social well-being and the intended environmental sustainability of the country.

HAVING ACCESS TO THE VOLUMES OF WATER NEEDED DAILY AND HAVING THE NATURAL SYSTEMS CONSERVED AND THE HYDRAULIC INFRASTRUCTURE FUNCTIONING IS ESSENTIAL FOR OUR LASTING SOCIAL WELL-BEING

Our demographic dynamics, their unequal territorial distribution, the occupation of hydrological regions, and the expansion of cities and metropolitan areas, together with the location and promotion of economic processes and policies for productive promotion and urban and regional development, have deep historical depth and institutional roots in the current national reality that, structurally, have created powerful inertias and serious problems that today are, or should be, urgent for critical attention and solution.

The water-wellbeing binomial is intertwined with these inertias and problems related to the institutional management of the social, economic, and ecological uses of water in Mexico, through concession titles, assignments, and discharge permits authorized by the National Water Commission (CONAGUA) through the Public Registry of Water Rights (REPDA) [see box]. From the beginning, there has been an emphasis on agricultural water use, through the deployment of irrigation districts and units, while the daily supply of drinking water and basic sanitation in homes and municipalities has lagged behind. The water supply for industrial activities and electricity generation grew for decades through the damming of the required flows, in the heat of economic modernization and the vertiginous industrialization process of the second post-war period, until the national economy reconfigured in the face of global influences, with less endogenous dynamism during the last 30 years.


The water-sustainability relation in Mexico comes from a more recent history, linked to internal convictions and external events expressed in the enactment of the General Law of Ecological Equilibrium and Environmental Protection (LGEEPA, 1988) and the consequent replacement of the Secretariat for Agriculture and Hydraulic Resources (SARH, which dated back to 1976) by CONAGUA (from 1989), institutionally relocated as the main decentralized administrative body of the Secretariat for the Environment, Natural Resources, and Fisheries (SEMARNAP in 1994; SEMARNAT today). Since then, there has been institutional tension in the design and implementation of public policy on water. Agricultural, industrial, and energy uses of water have always been considered a priority, while public supply and the daily service for drinking water and basic sanitation in homes and municipalities have gradually gained relevance, due to health concerns for half a century and to the constitutional reform dated in February 2012. Finally, the ecological conservation of watersheds, hydrological regions, aquifers, and flows are the emphasis of more recent public policies, whose attention should be a priority, although, unfortunately, they continue to exhibit a lower institutional hierarchy.

WATER AND WELLBEING
Institutional and public inertias matter because they influence our reality daily and are projected as a probable future in a significant way. Table 1 shows the formal classification of consumptive and non-consumptive uses of water and the way in which it is organized.

 Sistema Nacional de Información del Agua, CONAGUA. https://sinav30.conagua.gob.mx:8080/Estadistico/#/repda

Economic uses of water represent 85 percent of total consumptive uses and only 15 percent is destined to compliance with article 4th of the Constitution, through the satisfaction of the consumption demand that, with very considerable gaps, the population makes thanks to the public supply of water in homes and municipalities. On the other hand, practically all the volumes concessioned for non-consumptive uses are concentrated in hydroelectricity generation. The conservation of ecological flows does not run through these channels, but it should do so through policies and actions for the conservation and comprehensive management of watersheds, flows, soils, forests, jungles, wetlands, and other vegetation covers that circulate “green water,” an essential ecohydrological complement to “blue water” flows (GCEW, 2024).2 On a national scale, the two consumptive uses of water that have exhibited the most dynamic growth rates so far in the 21st century are: integrated industrial (three percent) and public supply (1.4 percent). Agricultural and related use registers a rate of change of 0.8 percent, slightly lower than the national average of 0.9 percent and has remained the largest user of water in the country for decades. For its part, the use of water for the generation of thermoelectricity during the same period shows a negative change (-0.43 percent) (Vega López, 2023).

MEXICO HAS A VOLUME OF RENEWABLE WATER OF AROUND 461 000 CUBIC HECTOMETERS PER YEAR, DISTRIBUTED IN A VERY HETEROGENEOUS WAY IN THE CONTINENTAL TERRITORY

With pronounced seasonal and annual oscillations related to known ecohydrological and geoclimatic characteristics, Mexico has a volume of renewable water of around 461 000 cubic hectometers per year, distributed in a very heterogeneous way in the continental territory. This reality is expressed as a structural feature when correlated with the magnitude and demographic dynamics of the country, the activities and economic processes located in different regions, states, and cities, as well as with the institutional management of water for decades: the largest water flows are concentrated in the south and southeast, with a smaller population settled there and also lower contributions to the national gross domestic product; while in the center, west, north, and northwest an inverse relationship is expressed. The map illustrates this structural feature.

 Elaboración propia con información de CONAGUA

The four hydrological-administrative regions (RHA, Spanish initials) of the south and southeast concentrate 68 percent of the available volume of renewable water; only 23 percent of the national population lives there, and their contribution to the country’s GDP is 16 percent. The other nine RHA are located in the center, west, north, and northwest and have only 32 per cent of the volume of renewable water; they concentrate 77 percent of the national population and contribute 84 percent of the GDP. These structural features have historical roots in the institutional management of water, whose sectoral and regional inertias have been shaped at different times, especially in recent times. What is impressive about this current reality is that four HAR account for two-thirds of the national economy and 60 percent of its demography: HAR XIII (Waters of Valle de México with 24.2 and 19.8 percent, respectively), HAR VIII (Lerma Santiago Pacífico with 20 and 20.2 percent), HAR VI (Río Bravo with 15.3 and 10.3 percent), and HAR IV (Balsas with 6.5 and 9.7 percent, respectively).

The relationship between the volumes of water concessioned for different consumptive uses (AC) and those corresponding to the available flows of renewable water per year (AR), results in a quotient known as water pressure (AC/AR). Of the 13 RHA of the country, only three register situations without water stress (V, X, and XI); two exhibit average degrees of water pressure, but increasing with worrying acceleration (IX and XII); seven show high degrees of water pressure (between 41 and 90 percent in RHA I, II, III, IV, VI, VII, and VIII) and, finally, RHA XIII, with a very high water pressure (129 percent). These structural features contextualize the aggravated gaps in Mexico and the relation of access to and daily use of drinking water, as well as access to basic sanitation coverage, with private toilets and drainage connected to the public network in homes, municipalities, and cities.

Having drinking water and basic sanitation in homes daily is one of the most effective social equalizers. It translates into greater family and collective hygiene, as well as better public health and effective social inclusion. Twelve years ago, in 2014, only 67 percent of the national population had daily drinking water in their homes; that is, about 40 million people lacking drinking water in their homes. Eight years later, in 2022, more than 50 million people were in this situation, as the daily coverage of such public supply fell to 61 percent of the country’s almost 129 million inhabitants at that time (SEMARNAT, 2025; INEGI, 2025a). Due to this setback, seven of the 13 RHA in the country exhibit worse records of daily coverage of drinking water in homes, in relation to the national average of 61 percent: RHA V, South Pacific (23.5 percent); RHA IV, Balsas (27.9 percent); RHA XI, Southern Border (45.5 percent); RHA X, Central Gulf (47 percent); RHA IX, North Gulf (53.3 percent); RHA VII, Northern Central Basins (56.4 percent), and RHA XIII, Waters of Valle de México (60.4 percent) (Vega López, 2026).

Basic sanitation coverage, with private toilet and drainage connected to the public network, registered an average proportion of 72.8 percent in Mexico in 2022, while in 2014 it had been 70.2 percent. This situation shows that more than 35 million people in Mexico do not have this service in their homes and that it took eight years to improve only 2.6 percent in this area. How long will it take us to meet these commitments for 2030? The state and regional cases with the largest gaps in basic sanitation, below the national average, are: Campeche, Yucatán and Quintana Roo (RHA XII, Yucatan Peninsula, 24.5 percent); Oaxaca and Guerrero (RHA V, South Pacific, 41.9 percent); Tabasco and Chiapas (RHA XI, Southern Border, 49.5 percent); Veracruz (58.2 percent); Morelos (62.1 percent); San Luis Potosí (63.7 percent); Nayarit (64 percent), and Hidalgo (69.3 percent). As can be supposed, having measured this evidence and with some inertias in progress, it can be said that, in this way, social welfare is not promoted nor is the country moving towards environmental sustainability.

 Sistema Nacional de Información del Agua, CONAGUA. https://sinav30.conagua.gob.mx:8080/Estadistico/#/repda

WATER AND SUSTAINABILITY
The quality of surface and underground water bodies matters a lot for social wellbeing, but also for environmental sustainability in terms of regional water resilience, better use of flows, and their inherent ecohydrological conservation. Table 2 summarizes the situation of the HAR in the country in relation to their degrees of contamination by anthropic pressures. With systematic sampling in around 5000 points of the national territory and analysis methodologies in specialized laboratories, water quality can be documented by considering different parameters.

The regions that present the most adverse situations by appearing with records of “contaminated and heavily contaminated” water quality, above the national average, in relation to three or four of the aforementioned parameters, are RHA IV Balsas (in all four), RHA VIII Lerma Santiago Pacific (in all four) and RHA XIII Waters of Valle de México (in three parameters). 

 Sistema Nacional de Información del Agua, CONAGUA. https://sinav30.conagua.gob.mx:8080/Estadistico/#/repda

In their side, the 653 aquifers also present formidable challenges, some due to overexploitation, others due to salinization, and still others due to marine intrusion. In addition to the presence of poor-quality traces, the overexploitation of aquifers generates serious subsidence effects (sinking due to drying up of aquifers), another of the current challenges related to vulnerability and risk management in cities and their metropolitan areas.

Finally, in relation to hydrological sustainability (of the water cycle) and water sustainability (of water as a resource), the best operation of hydraulic infrastructure is the circular economy of water. It will take a little longer to become a growing reality as long as the proportion of the volume of treated water over that of the wastewater generated and its subsequent use to cover different consumptive and non-consumptive uses is not significantly increased. Table 3 summarizes the most reliable figures in this regard. It is worth concluding by saying that there is valuable information to update the existing diagnoses for different territorial scales, but there is a need to strengthen political will, strengthen institutions, increase public budgets, and make public policies durable to pursue sustainable hydrological management, regular supply of water requirements, and an efficient operation of hydraulic infrastructure, consistent with the country’s net social welfare and with environmental sustainability.

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