Water Stress

Water stress is the condition in which demand for water exceeds the amount available during a given period, or in which poor water quality limits how the resource can be used. It is one of the central indicators for assessing the sustainability of water supply and the security of ecosystems and communities.

How water stress is measured

The most widely used metric is the ratio between freshwater withdrawals and renewable water availability:

Water stress = total freshwater withdrawals / renewable freshwater available (after reserving environmental flows)

Under SDG indicator 6.4.2, of which the FAO is the custodian, withdrawals above 25% of renewable resources indicate stress, and values above 75% are considered serious. The Aqueduct Water Risk Atlas (WRI) uses its own bands, classifying withdrawal-to-availability above 40% as high and above 80% as extremely high.

Drivers of water stress

• Population and urban growth, which raise domestic and municipal demand.
• Agriculture, which accounts for roughly 70% of global freshwater withdrawals (FAO).
• Industry and energy, particularly thermal power and mining.
• Climate change, which intensifies droughts and rainfall variability.

Consequences

• Depletion of rivers and aquifers, linked to blue water scarcity.
• Competition and conflict between sectors and across borders.
• Environmental degradation: salinisation, wetland loss and declining biodiversity.

Assessment tools

• The Aqueduct Water Risk Atlas (WRI) for global, current and future risk mapping.
• Baseline Water Stress, which compares withdrawals with renewable supply.
• The Water Poverty Index, which integrates availability, access and ecosystem capacity.

Mitigation strategies

• Integrated basin management that maintains ecological flow regimes.
• Water-use efficiency and precision irrigation in agriculture.
• Wastewater reuse and, where appropriate, desalination powered by renewable energy.
• Pricing and regulation to curb excessive demand and reward conservation.

Measuring and managing water stress is essential to protect basin resilience and the security of food, energy and health systems. At Manglai we help companies measure their water and carbon footprint and prepare their sustainability reporting. Discover how Manglai can help you.