Water Security
Water security is having access to sufficient amounts of safe drinking water. It is a significant component of sustainable societies.
Three things must come together for water security to exist: enough water in the first place (quantity), water that is safe to use (quality), and a reliable, affordable way to get it (accessibility). Managing risks such as droughts, floods, and pollution events is also part of the picture.
Water security matters across every dimension of human wellbeing:
- Health and sanitation: Clean water prevents waterborne diseases such as cholera, dysentery, and typhoid. Access to sanitation and hygiene services (WASH) is directly tied to disease prevention.
- Food security: Agriculture depends on reliable water inputs; without them, food production becomes unstable.
- Economic stability: Industry and energy generation require consistent water supplies.
- Ecosystem health: Freshwater ecosystems underpin biodiversity and fisheries.
Water security is not simply about whether water physically exists nearby.
A population can live next to a river and still be water-insecure if that water is contaminated, if there is no infrastructure to reach it, or if the cost of access is prohibitive.
Water insecurity is the opposite condition: where access to sufficient, safe, and affordable water is not guaranteed. It drives poverty, malnutrition, migration, and conflict. Its causes include physical scarcity, pollution from agriculture and industry, inadequate infrastructure, poor governance, and political instability.
Water scarcity and water insecurity are not the same thing. Scarcity describes a physical lack of water. Insecurity is broader: it includes social, economic, and political barriers that prevent access even where water exists.
Regions with abundant, stable rainfall (such as Scandinavia or Canada) tend to have high water security. Arid regions like the Sahel or the Arabian Peninsula face physical limits on supply. Climate change adds pressure everywhere by amplifying the variability of rainfall, increasing drought frequency, and driving saltwater intrusion into coastal aquifers as sea levels rise.
The western USA experienced a prolonged megadrought from 2000 to 2021 that reduced flow in the Colorado River, threatening water supplies for millions of people across seven states.
In Ethiopia and Yemen, chronic water insecurity compounds food insecurity and poverty.
Factors Affecting Freshwater Availability and Access
Social, cultural, economic, and political factors all shape whether people can access the freshwater they need. These factors do not operate in isolation: they interact and reinforce each other, producing very different outcomes for communities that may share the same physical water resources.
Social factors
Population growth raises total demand across domestic, agricultural, and industrial sectors. Urbanisation concentrates that demand, often straining infrastructure and depleting surrounding aquifers. Social inequality means that marginalised or rural communities routinely lack piped water or treatment systems, even within countries that are not physically water-scarce.
In Flint, Michigan (USA), a cost-cutting political decision to switch the city's water source led to lead contamination in drinking water.
The communities most affected were low-income and predominantly African-American, illustrating how social inequality and political decisions combine to create water insecurity.
Cultural factors
Religious and traditional practices shape both water use and water perception. In many low-income countries, women and girls carry primary responsibility for collecting water, which limits their access to education and employment. Societies with conservation-oriented values tend to manage water more sustainably.
In rural sub-Saharan Africa, women commonly walk several kilometres each day to collect water.
In India, the Ganges is considered sacred and used for ritual bathing, but pollution from cremations, sewage, and industrial discharge undermines its safety for the millions who depend on it.
Economic factors
Wealthier nations invest in advanced infrastructure that ensures consistent supply and treatment. In low-income settings, households that cannot access piped water often pay vendors a higher price per litre than connected households pay. Agriculture and industry together account for roughly 90% of global freshwater withdrawals, reducing what remains for domestic use. Investment in reservoirs, desalination plants, and wastewater treatment expands both access and quality.
Mexico City extracts groundwater at rates that have caused parts of the city to subside by up to 7 cm per year. The city simultaneously faces chronic shortages because its over-extracted aquifer cannot recharge fast enough to meet demand.
Political factors
Effective governance can ensure equitable distribution and long-term sustainability. Where governance is weak or corrupt, water resources are misallocated. Shared rivers create transboundary tensions when one nation's use reduces another's supply.
South Africa's National Water Act (1998) enshrines the right to water and prioritises human needs in allocation decisions.
At the regional scale, Ethiopia's Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile has generated tension with Sudan and Egypt, since Egypt depends on the Nile for approximately 98% of its freshwater supply.
These four categories of factor are interdependent. Political neglect tends to fall heaviest on communities already marginalised by social inequality. Cultural practices influence political decisions. Economic constraints prevent infrastructure investment. Effective management of freshwater therefore requires integrated approaches that address all four dimensions together.
Water Demand and Human Uses of Freshwater
Human societies undergoing population growth or economic development must either increase the supply of water or improve the efficiency of its use. Water is withdrawn for three main purposes: domestic use, agriculture, and industry.
Domestic use
Domestic use covers drinking, cooking, bathing, and sanitation. The WHO estimates that 50–100 litres per person per day meets basic needs. In practice, per-capita consumption varies enormously: a household in a high-income country may use ten times more water than one in a low-income country, because piped supply, washing machines, and garden irrigation all raise consumption.
In sub-Saharan Africa, over 300 million people live in areas where water scarcity limits domestic supply. Women and children often spend several hours each day collecting water from sources that may be unsafe.
Agricultural use
Agriculture is the largest single water user, accounting for roughly 70% of total global withdrawals. Irrigation greatly increases crop yields but also drives depletion of rivers and aquifers. Livestock farming is particularly water-intensive: producing 1 kg of beef can require up to 15,000 litres of water, compared with roughly 1,500 litres for 1 kg of wheat. Inefficient irrigation methods, particularly flood irrigation, compound the problem by losing large volumes to evaporation and surface runoff.
Industrial use
Industry accounts for approximately 20% of global water use, though the share varies by region and level of economic development. Water is used for cooling, cleaning, processing materials, and generating hydroelectric power. As economies shift from agriculture towards manufacturing, industrial water demand rises sharply.
In Germany, industrial water consumption represents more than 50% of total national use, driven primarily by energy generation and manufacturing.
By contrast, the average North American uses around 3 m³ of water per day, compared with approximately 1.4 m³ in Asia and 1.1 m³ in Africa, differences that reflect not just domestic habits but the embedded water in food and manufactured goods.
As populations grow and economies develop, societies face a choice: expand the total supply of water, or use existing supplies more efficiently. In practice, both strategies are usually needed together.