The Second Challenge to Safe Drinking Water: Water Availability and Scarcity
Safe drinking water must be available in sufficient quantities, but freshwater resources are not evenly distributed around the world. In some regions, communities face naturally limited water supplies, while others have freshwater resources but struggle with infrastructure, treatment capacity, or the cost of delivering water.
This makes water availability and water scarcity a major challenge for drinking water security. The issue is not simply how much water exists on Earth, but how much freshwater can actually be accessed, treated, and reliably supplied to people.
Why Is Freshwater Availability Limited?
More than two-thirds of the Earth's surface is covered by water, but most of it is seawater and cannot be used directly as drinking water without desalination.
Only a small proportion of the Earth's water exists as freshwater. The source material estimates that approximately 2.7% of global water is freshwater, while only around 1% is readily available in sources such as rivers, lakes, and accessible groundwater.
Much of the remaining freshwater is stored in glaciers, ice caps, or deep aquifers that are difficult to access.
This creates an important distinction between freshwater resources and usable drinking water resources. A region may have substantial water resources while still experiencing difficulties providing reliable drinking water.
How Does Water Availability Change by Season?
Water availability can also vary considerably throughout the year. In some developing regions, particularly parts of sub-Saharan Africa, communities may rely on different water sources depending on seasonal conditions.
During the rainy season, rivers and other surface water sources may provide an important supply. During dry periods, communities may increasingly depend on groundwater from wells and boreholes.
This seasonal shift can place additional pressure on groundwater resources and water supply infrastructure. It also means that drinking water systems need to be capable of responding to changes in water source, water quantity, and water quality.
Reliable drinking water supply therefore depends not only on having a water source, but also on maintaining the infrastructure needed to collect, treat, store, and distribute that water.
How Does Population Growth Increase Water Scarcity?
Freshwater resources are relatively limited, while global demand for water continues to grow.
Over the past 40–50 years, global freshwater withdrawals have approximately doubled. Population growth, agricultural irrigation, industrial development, and increasing domestic demand have all contributed to higher water consumption.
The challenge becomes more significant when population growth occurs in areas where freshwater resources are already under pressure. According to the figures in the source material, approximately 2.8 billion people across 31 countries were facing serious water-resource challenges.
Why Is Groundwater Important for Drinking Water Security?
Groundwater provides an important source of drinking water in many regions, particularly where surface water is limited or highly seasonal.
However, groundwater resources can also become stressed when extraction exceeds natural recharge. Agricultural irrigation is an important factor in this imbalance. Excessive groundwater extraction can reduce the reliability of future water supplies while also creating challenges for agriculture and food production.
For communities that depend heavily on wells and boreholes, groundwater management is therefore closely connected to long-term drinking water availability.
Why Can Water-Rich Countries Still Face Water Shortages?
Water scarcity is not determined solely by the physical amount of freshwater available. Ethiopia, for example, has extensive freshwater resources and more than eight major river basins, yet parts of the country continue to experience difficulties in providing reliable safe drinking water. In contrast, South Africa receives approximately 450 mm of rainfall per year and faces naturally greater water-resource pressure.
Economic resources and infrastructure can therefore be just as important as natural water availability. A community may have freshwater nearby but still lack the infrastructure needed to collect, treat, store, or distribute it. In some developing regions, people living in informal settlements have reportedly paid 5–10 times more per unit of water than residents connected to urban water systems.
What Role Does Water Treatment Play in Water Availability?
When freshwater resources are limited, making better use of available water becomes increasingly important. Water treatment can help make different water sources suitable for their intended applications, while disinfection plays an important role in microbial control.
Depending on the source and quality of the water, treatment may involve filtration, clarification, adsorption, membrane processes, desalination, and disinfection.
For microbial control, chlorine-based drinking water disinfection remains an established treatment approach. Chlorine-based products such as sodium dichloroisocyanurate (SDIC/NaDCC) and trichloroisocyanuric acid (TCCA) can release available chlorine in water and may be used in appropriate water treatment applications where permitted by local requirements.
The purpose of treatment is not simply to increase the quantity of water available. It is also to help ensure that available water can be used safely and reliably.
How Severe Is Global Water Stress?
The pressure on freshwater resources is already significant in many parts of the world.
According to the latest assessment from WRI's Aqueduct 4.0, 25 countries are now facing extremely high water stress, home to around 2 billion people, roughly one-quarter of the global population. UN-Water estimates that approximately 4 billion people experience severe water scarcity for at least one month each year, while 2.1 billion people still lack safely managed drinking-water services worldwide. The economic implications can also be substantial. Under severe water-stress scenarios, some affected economies could face GDP losses of approximately 6–14% by 2050.
Conclusion
Water scarcity is not simply a problem of having too little water. It can result from limited freshwater resources, seasonal variation, groundwater depletion, rising demand, inadequate infrastructure, and the cost of supplying treated water.
As freshwater withdrawals increase and populations continue to grow, protecting existing water resources and improving the efficiency of water use will become increasingly important.
For drinking water systems, this means looking beyond the source itself. Reliable water supply requires sufficient freshwater resources, effective water treatment, appropriate drinking water disinfection, dependable infrastructure, and the ability to deliver treated water at a reasonable cost.
Water availability and scarcity therefore represent a fundamental challenge to safe drinking water. Ensuring that water is not only present, but also accessible, treatable, reliable, and available when communities need it, is an essential part of long-term drinking water security.
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Hebei Liuhe Chemicals Co., Ltd. is a factory-direct manufacturer specializing in SDIC, TCCA, cyanuric acid, sulfamic acid, and melamine cyanurate for global B2B customers. Established in 2015, Liuhe operates large-scale production facilities with automated manufacturing lines and testing equipment, supplying consistent-quality water treatment and disinfection chemicals for swimming pools, drinking water treatment, industrial water treatment, and other applications. Contact us for product specifications, technical information, and business cooperation.