Under normal circumstances, for adults, the daily water intake should be 1.5-2.0 L. But the elderly should be reduced as appropriate, because the basal metabolic rate of the elderly is lower, and many elderly people’s heart and kidney function is not complete, if the intake of too much water, will lead to swelling. So for the elderly, you can consume 1.0-1.5L of water per day. For children and adolescents, the body is in a state of high metabolism, you can intake 2.5-3.5L of water, are normal levels. For pathological conditions, such as heat stroke or acute inflammation of the gastrointestinal tract, the number of vomiting or diarrhea increases, you should add 0.5-1L of drinking water on top of the original intake of water.