Water Insecurity – When water availability is not enough to ensure the population of an area enjoys good health, livelihood and earnings; not enough water at times

Water Insecurity can be caused by water insufficiency or poor water quality. 

The water was supposed to be in a secure (water insecurity) unit, but it's all gone.

Water insecurity is defined as the lack of a reliable source of water, of appropriate quality and quantity to meet the needs of the local human population and environment. 

There's a big difference between water insecurity and water deficit.

Water insecurity can occur even in countries that have plenty of water due to, for instance, pollution of the supply or inability to access it; while a country that has a water deficit has a physical shortage of water.

Other factors that can make a water supply insecure include saltwater encroachment along coasts, contamination from agriculture and industrial water pollution.