In 1987 the World Commission on Environment and Development (Brundtland Commission) warned in the final report, Our Common Future, that water was being polluted and water supplies were overused in many parts of the world. The water environment and development are strongly interdependent. The state of the hydrological regime, its water quality and ecosystems are major factors contributing to human well-being. The ocean is the source of most of the world’s precipitation (rainfall and snowfall), but people’s freshwater needs are met almost entirely by precipitation on land, with a small though increasing amount by desalination. Due to changes in the state of the ocean, precipitation patterns are altering, affecting human well-being. Ocean changes are also affecting marine living resources and other socio-economic benefits on which many communities depend. The availability, use and management of freshwater, and of aquatic ecosystems in general, are keys to development and human health. (Malta, 2007). Despite the relevance of freshwater to human health and ecosystem quality, impacts on water resources have only been described qualitatively. With the exception of the Ecological Scarcity 2006 method (UBP06), the Ecological Scarcity method quantifies eco-factors on the basis of defined environmental targets without addressing specific damages to human health and ecosystems (Owens, 2001). Several hydrological assessments of global water resources exist, and different models of global water availability and resulting water stress have been developed (Vörösmarty et al., 2000) allowing for the assessment of water shortage in climate-change and varying population-dynamics scenarios. However, none of these methods explicitly considers cause−effect relationships between water use and environmental impacts. The Water Stress Index (WSI) indicates the portion of water use (WU) consumptive that deprives other users of freshwater. WSI may serve as a simple screening indicator for the assessment of water use, accounting for water availability and withdrawals. The consideration of temporal variability of water availability in WSI allows for assessing increased impacts in specific periods. While infrastructure may enable sufficient water storage and hence mitigate water stress for human needs, ecosystems will still be affected and additional water will be evaporated from the surfaces of water-storage systems (Alcamo et al, 2003).The goals of this paper are to calculate WSI and evaluate impacts of water use on the human health, ecosystems and resources of one ton apple production in West Azerbaijan province in Iran.