Technical Abstract: The contributions of drinking water to the mineral nutrition of individuals are functions of the mineral contents of that water and the rate of water consumption of those individuals. The mineral contents of water supplies vary considerably, and many are processed to remove minerals. In fact, the processing of water, by distillation or reverse osmosis, is rapidly growing as the principle source of new fresh water worldwide. These methods yield water of high purity and, thus, very low mineral content. Because body water is tightly regulated factors that affect water losses from the body (environmental conditions, physical activity) affect daily water needs. Food can provide as much as a liter per day, but total fluid requirements can range from 2-16 L/day. While most processed drinking water provide few, if any, essential nutrients, such water constitutes a potential vehicle for delivering essential minerals to troops many of whom will have high fluid intakes during hot weather duty. This presents opportunities for the military to develop mineral content standards for drinking water produced and/or purchased for troop consumption. Such standards could be useful in ensuring adequate intakes of key minerals not easily achieved by dietary means.