Signs That You May Be Dehydrated: Dehydration occurs when the loss of body fluids, mostly water, exceeds the amount you take in. When more water is moving out of individual cells in the body than being taken in, the body then doesn't have enough water and other fluids to carry out its normal functions. Mild, even moderate, dehydration can be treated simply by drinking more fluids that contain electrolytes (or salts) that have been lost. However, if dehydration is unrecognized or left untreated, it has the potential to lead to death. It is very important to understand the signs of dehydration before the condition worsens.