Underground water resources play a crucial role in fighting drought and securing drinking water. In Spain, however, aquifers are increasingly polluted, with nitrates from intensive farming and industrial activities contributing to contamination. Overuse compounds the problem, threatening the reliability of this essential supply.
Spain faces a groundwater crisis so palpable that environmental groups, scientific bodies, and even the European Union have sounded alarms. The visible results are clear: water scarcity is a growing challenge. In dry regions, citizens have long endured restrictions during lean months, yet the pressure has become chronic. Drought now feels like a persistent health issue, and much of the underlying cause lies beneath the surface.
UNESCO data show underground reserves provide half of the world’s drinking water. In Europe, dependence is even higher: Brussels estimates that 65 percent of urban water and a quarter of irrigation water flow beneath the ground.
Depth of wells in Spain Scott Jasechko
Recent statistics from the Ministry for the Ecological Transition (Miteco) show the problem in stark terms: around 30 percent of groundwater in Spain is compromised. While many regions rely on a hybrid system drawing from both aboveground and underground sources, some areas depend almost entirely on aquifers. With these figures, groundwater contamination becomes a pressing crisis.
Excess nitrogen and phosphorus
A term to know is eutrophication, describing the surplus of nitrogen and phosphorus that degrades water quality. These nutrients feed unchecked plant and microbial growth, which depletes oxygen and muddies the waters.
Greenpeace notes that 44 percent of underground bodies in Spain are in poor condition.
The consequences are severe for biodiversity and water security. Algae and related organisms can produce harmful substances for aquatic life and birds. The most common culprits are agriculture, intensive animal farming, urban waste, and industrial activities. When economic activity and sustainable development collide, the environment often pays the price.
Overuse without regeneration
Greenpeace reports further that 44 percent of groundwater bodies in Spain are in poor condition. The organization warns that overusing the water cycle beyond its recharge leads to irreversible pollution, a situation worsened as climate change intensifies drought. It is important to separate two issues: the quantitative condition (around 27 percent) and chemical integrity (up to 30 percent), with 14 percent failing in both.
Fish killed by disturbed waters Jason Mintzer/Shutterstock
Across studies, the diagnosis remains consistent. Citizen Network’s measurements show almost 60 percent of Spanish groundwater carries nitrates, with 37 percent exceeding the legal limit. The Ministry of Ecological Transition acknowledges that about 40 percent of the water masses fail to meet the European Water Directive’s minimum standards.
The role of macro farms
Regionally, the Ebro River basin and areas such as Catalonia, Castilla y León, Mallorca, and Gran Canaria stand out as hotspots. Yet the problem is global. As pollution grows where agriculture dominates and in regions saturated by large-scale farming, Greenpeace experts emphasize that those intensive operations shoulder a large share of responsibility.
Large cattle ranches are increasingly common, and their environmental footprint extends beyond animal welfare. Intensive meat, dairy, and egg production can disrupt ecosystems when waste accumulates and nitrate levels surge. A major part of the remedy lies in regulating these large enterprises.
Macro farms often count thousands of animals, and their excrement releases nitrates that percolate through soil and into aquifers. While manure has long been hailed as a soil booster, over-application becomes a pollution risk. Experts point to tighter regulation as a key step toward improving groundwater quality.
An action plan
Spain faces a level-one problem that has drawn scrutiny from the European Commission for nitrate management. The Water Framework Directive requires all groundwater bodies to be in good condition by the end of 2027, a goal many consider unlikely in the Spanish context. Europe has signaled a clear expectation that this target will not be met. Contamination, once established, can take decades to reverse.
The European Commission opened a case against the Government for not meeting nitrate standards.
To tackle these shortcomings, the Ministry of Ecological Transition has laid out an action plan aimed at preserving this vital resource. The plan emphasizes the water quality and availability needed for households, industry, and agriculture alike, while highlighting the strategic role of groundwater during drought. The approach also calls for better governance, information, and management aligned with environmental protection and ecosystem health. The overarching aim is sustainable use across different sectors.
High nitrate content remains a central pollution issue in parts of Spain. The contamination typically traces back to agricultural and livestock practices, manure management, irrigation, and animal residues. The objective is to improve information, governance, and stewardship so groundwater stays quantitatively and chemically sound while supporting protected areas and related ecosystems.
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Marco Dentz, researcher at IDAEA-CSIC, has described groundwater degradation as a complex challenge in need of science-driven solutions. The Karst project, led by researchers including Dentz and funded by the European Research Council, seeks to map underground karst systems to predict flow patterns and pollutant transport. The project involves collaboration across Spain, France, Slovenia, and Switzerland, with substantial European funding to support multidisciplinary teams.
The Karst project outlines three phases: first, measuring water flow laws in channels and caves with complex geometries; second, classifying cave networks and creating computer models; third, mathematically modeling water and contaminant transport to assess flood, drought, and spill risks and to guide prevention and recovery measures.
The program demonstrates how European funding can accelerate cross-border science, with a focus on practical outcomes for water resilience.
The project notes that karst aquifers are particularly fragile because rapid flow can carry pollutants quickly to water supplies during storms, potentially affecting rivers and downstream users. Contaminants originate from diverse sources including industry, agriculture, and waste sites, and pinpointing the origins requires forensic hydrology methods. Short-term solutions depend on the specific site and aim to estimate contamination levels and design targeted prevention and remediation measures.
Sources and contact information are provided within the environmental department for further context and collaboration opportunities.