- Nearly one-third of monitored groundwater wells showed declining water levels.
- Researchers reviewed groundwater trends in 47 countries over 20 years.
- Falling groundwater levels are affecting farms, drinking water, and ecosystems.
- Some regions are also seeing rising groundwater that can cause flooding and damage.
- Scientists say stronger monitoring programs are urgently needed.
Wednesday, May 20, 2026 — Groundwater is often out of sight and easy to overlook, but it quietly supports farms, cities, rivers, wetlands, and drinking water supplies around the world. A major international study published May 19, 2026, found that many groundwater systems are under growing stress, with warning signs now appearing across large parts of the globe.
The study, published in Environmental Research Letters
, analyzed groundwater monitoring records from more than 42,000 wells in 47 countries over roughly two decades. Researchers found that about 29% of monitored wells showed declining groundwater trends, while 18% showed rising water levels. Both situations can create serious problems for communities, agriculture, and the environment.
Groundwater is the largest store of liquid freshwater on Earth. The researchers noted that it supplies about 40% of irrigation water worldwide and provides drinking water for roughly two billion people.
The report paints a mixed global picture. Some areas are losing groundwater rapidly because of overpumping, drought, and climate pressures. Other regions are seeing groundwater rise because of changing rainfall patterns, irrigation practices, sea level rise, or reduced pumping.
The researchers stressed that both rising and falling groundwater levels can cause damage.
Why Falling Groundwater Matters.
When groundwater levels drop, wells may stop producing enough water. Farmers often must drill deeper wells and spend more money on pumping. Rivers, wetlands, and springs can dry up. In some places, the ground itself can slowly sink, damaging roads, canals, pipelines, and buildings.
The study identified several major hotspots of groundwater decline.
In the United States, significant declines were found across western states, portions of the High Plains aquifer, and parts of the East Coast. The Central High Plains region stood out as one of the clearest examples of long-term depletion. Researchers found that 81% of monitored wells there showed declining groundwater trends.
That region supports a large share of American agriculture, including corn, wheat, and cotton production. As groundwater levels fall, irrigation becomes more expensive and less reliable. Some farmers are already shifting from irrigated farming back to dryland agriculture because water is becoming harder to reach.
The study also highlighted severe groundwater declines in northern India, Chile, Jordan, Mexico, parts of Spain, and portions of South Africa.
In Chile’s Central and Norte Chico regions, groundwater declines have become so serious that some communities now rely on water deliveries by truck. Researchers cited examples where families received only small amounts of emergency water each day.
Mexico City was identified as another major concern. The city depends heavily on groundwater for its water supply. Researchers found that overpumping has caused groundwater levels to drop by roughly half a meter per year in many areas. The falling water table has also changed underground flow patterns, allowing pollution to move into important drinking water aquifers.
Rising Groundwater Can Also Be Dangerous.
While groundwater depletion receives most of the attention, rising groundwater can create a different set of problems.
Higher groundwater tables can flood basements, damage roads and underground infrastructure, weaken building foundations, and interfere with septic systems and wastewater disposal. In coastal areas, rising sea levels can also push groundwater closer to the surface.
The report noted rising groundwater trends in parts of the United States, including Florida and Georgia, as well as sections of Europe and Asia.
In some cases, rising groundwater may reflect recovery after reduced pumping or wetter conditions. In other areas, it may signal growing flood risks.
Climate Change Adds More Pressure.
The study repeatedly pointed to climate change as an important factor influencing groundwater systems.
Longer droughts, shifting rainfall patterns, rising temperatures, and more extreme weather are changing how water moves underground. In some regions, recharge is slowing while demand for irrigation continues rising.
Researchers also warned that groundwater systems often respond slowly. Damage may not become obvious until years or even decades after overuse begins.
That delayed response can create a false sense of security. Water supplies may appear stable for years before sharp declines suddenly emerge.
Monitoring Still Has Big Gaps.
One of the strongest messages in the report was the need for better groundwater monitoring.
The researchers said many countries still lack long-term monitoring systems, making it difficult to understand what is happening underground before serious damage occurs. The study relied heavily on in-situ monitoring wells, meaning actual physical measurements taken directly from the ground rather than satellite estimates alone.
The authors argued that long-term groundwater monitoring is essential for understanding trends, evaluating policies, and protecting water supplies for future generations.
The report ultimately concluded that groundwater problems are no longer isolated local issues. Instead, they are becoming a worldwide challenge tied directly to food production, economic stability, ecosystem health, and drinking water security.
As drought pressures continue building across many regions of the world, including the American West, the findings offer another reminder that much of the planet’s freshwater future depends on what is happening underground.
Citation.
In-situ groundwater level monitoring reveals worldwide status, trends and impacts
Feifei Cao, Elie Gerges, Claudia Ruz Vargas, Andrew R Pearson and Elisabeth Lictevout
Published 19 May 2026
Environmental Research Letters, Volume 21, Number 10
Citation Feifei Cao et al 2026 Environ. Res. Lett. 21 103002
DOI 10.1088/1748-9326/ae651f
