COLOMBIA IS ALREADY USING ITS GROUNDWATER. THE REAL QUESTION IS WHETHER WE KNOW HOW TO MANAGE IT
Morroa is the warning in numbers
In 2015, Carsucre reported natural recharge of 45 to 75 litres per second for the Morroa aquifer, against withdrawals of 1,000 to 1,200 litres per second. In the same report: water levels have been falling by one to two metres a year since 2003.
That is not a marginal imbalance. Carsucre reported abstraction exceeding natural recharge by well over an order of magnitude.
The aquifer supplies eight municipalities: Sincelejo, Corozal, Ovejas, Morroa, Los Palmitos, San Juan de Betulia, Sampués and El Carmen de Bolívar.
No adjective is needed. By 2015, Carsucre was already documenting a sustained decline dating back to 2003.
The underlying question
The problem is not whether groundwater exists. The problem is whether withdrawals are being made within the recharge capacity of the system.
Those are two different questions, and in Colombia it is almost always the first one being debated.
Groundwater in Colombia today
The National Water Study of 2022 (the 2026 edition remains in development, with an advance report published in August 2026) identified 67 aquifer systems in the country and an inventory of 68,397 water points, 6.5% more than in 2018 and 35.5% more than in 2014. Of those, 38,817 are shallow wells (56.8%), and 17,007 are drilled wells (24.9%). The remainder are springs (6.4%) and filtration galleries and other abstraction methods (1.9%).
More than 175 municipalities depend fully or partly on groundwater.
At the same time, 78% of Colombian territory could use aquifers, yet only around 15% of these systems are characterised. Ten environmental authorities run systematic monitoring networks, covering 2,273 points nationwide. The Cundinamarca environmental authority and the departmental government are working to expand the monitoring network from 15 to 30 piezometers.
That is the current contrast: a broad inventory and systematic monitoring capacity that remains limited.
An aquifer is not a tank
This is the underlying confusion, and it is an engineering confusion, not a policy one.
Anyone who has worked in the subsurface knows the difference between stored volume and deliverability. A reservoir can hold a great deal and deliver very little: permeability, connectivity, and pressure regime matter alongside volume.
The same basic distinction applies to an aquifer, with one additional fundamental variable: recharge.
An aquifer can store a large volume of water and still move progressively into deficit if abstraction persistently exceeds recharge.
The analogy goes that far and should not be stretched further. An aquifer has recharge, discharge, interaction with surface water bodies, storativity and boundary conditions that have no simple equivalent in a hydrocarbon reservoir. What does carry across intact is the distinction between storage and sustainable deliverability, and treating those two as the same thing sits behind a good share of the aquifers now in trouble.
Two documented cases
Bogotá, October 2024. Bogotá has 528 drilled wells on record, between 30 and 500 metres deep, but only 64 active groundwater concessions were reported in October 2024: 21 industrial, 39 mixed-use, 3 irrigation and 1 livestock and irrigation. The remaining drilled wells should not be assumed to represent active unpermitted abstraction. The report itself states that the rest are not in operation, and the published figure does not establish how many are still running, or under what status.
What follows from that is two questions, not two conclusions. The first is how many of those wells are still operating and on what legal basis, which is precisely what the published figure does not settle. The second is a fact: the district collects around COP 23 million a year from those concessions, with those funds earmarked for aquifer conservation.
As of July 2025, the district environment authority runs what it calls level brigades twice a year across around 100 concession points: authorised users shut down abstraction for four consecutive days while daily piezometric measurements are taken to assess aquifer recovery against the historical record. That is precisely the measurement that was missing. The two numbers should not be read as a series: 64 concessions in October 2024 and around 100 concession points under monitoring in July 2025 come from different sources and different criteria, and cannot be subtracted from one another.
San Andrés, 2018 and 2025. Eighty per cent of the archipelago's population depends on groundwater drawn from shallow wells, deep wells and augered wells. On an island, fresh water floats on salt water. If abstraction persistently exceeds recharge, the risk of saline intrusion and deterioration of water quality increases.
The conceptual and numerical hydrogeological model of the San Andrés aquifer, in draft form for review by the contract supervisory committee, dated October 2025, puts figures to that. Of the 2,071 wells holding some form of hydrogeological information, only 57 have a lithological log and of those only 13 have information on the position of the screens. CORALINA recorded 23 wells under concession in 2024. And conductivity confirms it: wells in the central urban area exceed 5,000 to 10,000 µS/cm during abstraction, and in the San Luis coastal formation they pass 30,000 µS/cm. These are very high salinity values, which the draft associates with marine influence on the aquifer.
2,071 wells and 57 lithological logs. That is the real size of the gap. It is not only a regulatory problem; it is also a problem of information and monitoring.
An aquifer is not over-abstracted because someone decides to over-abstract it. It is over-abstracted because each user makes a reasonable decision separately and nobody adds them up.
The counterpoint: Valle del Cauca
In the first half of 2026, Valle del Cauca recorded 1,828 active wells, abstracting 369 million cubic metres a year. That is 35% of the system's recharge. The regional authority applies a management guideline of up to 50% of annual recharge.
It is worth reading that carefully. It is not that Valle abstracts little. It does so at considerable scale. What Valle has is the number: it knows what comes in, it knows what goes out, and it has a reference point to measure itself against.
That is the whole difference. Not abstracting less. Knowing how much is being abstracted, and against what.
This is not only Colombian
Groundwater is roughly 99% of all liquid fresh water on Earth. It supplies half the volume withdrawn for domestic use worldwide and around 25% of water withdrawn for irrigation. It is not a marginal resource. It is the resource.
A study published in Nature in January 2024 examined more than 170,000 monitoring wells across 1,693 aquifer systems in over 40 countries, together accounting for about 75% of global groundwater withdrawals. The result: 36% of monitored systems are falling by more than 10 centimetres a year, 12% by more than 50 centimetres a year, and the rate of decline is accelerating in roughly 30% of the systems where the historical comparison could be made.
And the finding that matters: some aquifers recovered. Albuquerque in New Mexico and Bangkok in Thailand reversed decline through conservation policy, interbasin transfers and the use of surface water and floodwaters.
In March 2026, the same lead author published in Science a review of 67 documented cases of aquifer recovery across six continents. Three families of intervention appear: alternative water supplies, present in 81% of the cases; policy and market interventions, in 52%; and artificial recharge, linked to recovery in 48%. Two-thirds of the cases combined interventions from more than one family, and only 11 relied on a single strategy.
The author flags what matters most here: the fact that an aquifer is recovering at a given moment does not mean the work is done. Green Bay, in Wisconsin, recovered and then fell again decades later when demand rose, and had to be dealt with a second time. His recommendation is to keep measuring after the initial recovery, so that management can adapt.
The conclusion is not that groundwater runs out. It is that groundwater responds to what is done with it, in both directions.
The second cost of abstracting without a permit
The debate almost always stops at volume. There is a second cost, less visible and potentially far harder to reverse: contamination.
A badly completed well, or one without an adequate sanitary seal, can create a hydraulic pathway between shallow levels and the deep aquifer, allowing sewage, leachate, agrochemicals or other contaminants to enter.
Groundwater contamination can persist for decades, and remediating it at aquifer scale can be extremely difficult and costly. That is why control of well design, construction, and completion is part of protecting the resource, not an administrative detail.
What has to be known before drilling
The regulation exists. Decreto 1076 de 2015 separates prospecting and exploration from the groundwater concession itself, and Resolución 330 de 2017, as amended by Resolución 799 de 2021, sets the technical code.
The challenge is turning it into information, monitoring, enforcement, and operating decisions. The minimum information for a responsible decision is this:
1. Appropriate hydrogeological and geophysical characterization. Drilling should begin with a site conceptual model and sufficient information to select location and depth. Methods such as vertical electrical sounding or electrical resistivity tomography can support that assessment; the appropriate technique depends on the geometry and geological complexity of the target.
2. Which aquifer is being targeted. A shallow Quaternary unconfined aquifer and a deep confined aquifer are not the same decision: depth, design, contamination risk and the sustainability of the yield all change.
3. The neighbouring wells and their history: depth, yield, static level, dynamic level, water quality, and how those values have moved over time.
4. The expected water quality and the intended use, because water fit for irrigation may not be fit for human consumption, and that is settled before drilling, not after.
5. The actual sequence of the permit. The regional authority does not authorise a flow rate at the outset. It first authorises construction of the well. The abstraction rate is set afterwards, once the well is built and the pumping test measures drawdown. Anyone offering a guaranteed yield before drilling is selling something that does not exist yet.
6. The full design, not a hole. A well includes casing, screens, gravel pack, sanitary seal, development, and testing. Casing diameter constrains the pump that can physically be installed, but sustainable yield is governed by the combined response of the aquifer and the well, including transmissivity, well efficiency, and allowable drawdown. The pump should be selected for that capacity, not used to define it.
Five actions
Measure the aquifer. Measure the wells. Measure abstraction. Protect recharge. Adjust pumping.
In that order, and permanently. None of the five requires technology Colombia does not have.
The right question
The question is not whether Colombia has groundwater. It does: 67 aquifer systems have been identified, groundwater use potential has been reported across roughly 78% of the territory, and more than 175 municipalities already depend on it fully or partly.
The question is whether we are going to manage it with numbers or carry on managing it with assumptions.
Morroa shows what can happen when abstraction and recharge stop balancing. The 67 international cases documented in 2026 also show that recovery is possible, normally through a combination of measures and sustained monitoring.
Technical note on the figures. National inventory data come from the National Water Study of 2022 and its publication in October 2026; the 2026 edition remains in development, with an advance report published in August 2026. The Bogotá figures are from October 2024 and July 2025, Morroa from the 2015 Carsucre report, and San Andrés from 2018 and from the October 2025 hydrogeological model, which is a draft under review by the contract supervisory committee and is cited as such. On Bogotá: the El Tiempo report gives 528 drilled wells in the body text and 580 in an image caption; the body figure is used and the discrepancy is recorded here. That same report states that the wells without a concession are not in operation, so the difference between drilled wells and concessions is not read as active unpermitted abstraction. Each case is presented with its date and should not be read as the current state of that system. Where a range is given, it is the range in the source. On Morroa: at the time of Carsucre's 2015 report, abstraction was roughly 13 to 27 times the reported natural recharge range, depending on which extremes are compared (1,000/75 = 13.3; 1,200/75 = 16; 1,000/45 = 22.2; 1,200/45 = 26.7). No independent hydrogeological estimates are introduced; the ratios above are arithmetic calculations derived directly from the ranges reported by the source.
SOURCES
Normatividad / Regulations
1. Decreto 1076 de 2015, Decreto Único Reglamentario del Sector Ambiente y Desarrollo Sostenible
2. Resolución 330 de 2017, Ministerio de Vivienda, Ciudad y Territorio. Adopta el Reglamento Técnico del Sector de Agua Potable y Saneamiento Básico, RAS. 08-06-2017
3. Resolución 0799 de 2021, Ministerio de Vivienda, Ciudad y Territorio. Modifica la Resolución 330 de 2017
Official and technical sources
4. Estudios Nacionales del Agua, IDEAM. Incluye el Estudio Nacional del Agua 2022 y el Reporte de avance ENA 2026, publicado el 06-08-2026
5. Panel de expertos sobre demanda y huella hídrica en el marco del Estudio Nacional del Agua ENA 2026, IDEAM, 21-02-2025
6. Estado de las aguas subterráneas en Colombia, IDEAM
7. Modelo hidrogeológico conceptual y numérico del acuífero de San Andrés, Observatorio CORALINA, versión preliminar para revisión, octubre de 2025
8. Secretaría de Ambiente intensifica mediciones de aguas subterráneas en Bogotá, Alcaldía Mayor de Bogotá, 05-07-2025
9. El agua subterránea, recurso por investigar, Minambiente
Scientific literature
10. Jasechko, S. et al. Rapid groundwater decline and some cases of recovery in aquifers globally. Nature, 24-01-2024
11. Jasechko, S. Global cases of groundwater recovery after interventions. Science, 2026, 391(6791), 1218-1228. DOI: 10.1126/science.adu1370
12. UN World Water Development Report 2022: Groundwater, making the invisible visible, UNESCO
News coverage
13. Acuífero de Morroa en riesgo de desaparecer por sobreexplotación, El Universal, 17-11-2015
14. Acuíferos en San Andrés, un recurso vital en vía de extinción, Radio Nacional, 15-03-2018
15. Concesiones de aguas subterráneas en Bogotá, El Tiempo, 07-10-2024
16. ¿Son las aguas subterráneas una opción viable ante la escasez de agua que se nos viene?, El Tiempo, 04-10-2026
17. Global groundwater levels declining rapidly, but they can recover, University College London, 24-01-2024
18. Why some regions are winning the fight against groundwater depletion, UC Santa Barbara, 20-03-2026
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