This article examines the theoretical and practical risks to water security, which is rapidly declining in many parts of the world, particularly in drylands. Water security is threatened by current land-use developments and over-utilization of groundwater. About 70 per cent of freshwater resources is globally used by irrigation agriculture. Interrelated water and food shortages may occur in the 21st century as the predictable outcome of current developments. This may lead to regional famine and political instability. Unpredictable contingencies, such as drought, earthquakes, terrorism, conflict and war, can also affect water security in a negative and dangerous way. Predictable and unpredictable, adverse developments vis-à-vis water security require more theoretical and practical studies. The important linkage between contingency planning and crisis management has to be developed and refined, including terminology. Safe underground water resources must be identified and developed in every nation and province as strategic reserves in civil emergency planning.