You want to avoid having your urine appear dark yellow in color. This is an indication that you need to increase your intake of water. Another thing that matters is maintaining the proper electrolyte balance within your body. This is especially true in desert and high altitude environments. Your body needs sodium, chlorine, magnesium and potassium compounds to maintain the electrolyte balance.
Salt intake helps.
Water is located in a variety of places, including streams, lakes, ice, snow, rainfall and dew on plants. Study the things and activities around you. Observe birds, animals and plants. But it is the presence of organisms in the water than are your main survival concern. To disinfect water, filter it first by pouring it through a filter, such as a handkerchief.