Finding water is one of the most important and time-sensitive issues facing anyone out on the trail--we each require a minimum of two liters per day. Once that need begins to go unfulfilled, hikers may experience a lack of energy and accompanying weakness, which may quickly lead to more severe effects, such as poor blood pressure, a rapid heartbeat and delirium. But even in an emergency, it is not safe to use just any water you come across.
While that isolated stream may look crystal clear and pure, it may be home to microorganisms that can cause ongoing severe diarrhea and vomiting, turning simple dehydration into a potentially life threatening situation.
Giardia and cryptosporidium are common parasites found in most backcountry sources of water. Drink from one of these sources without purification and you could do far more damage to your health than simply going without.
Treat all water before your drink. Purification tablets are helpful, but be aware that the effectiveness of iodine (may not kill either of these parasites) and chlorine bleach (cryptosporidium is highly resistant) have both been called into question. Commercial filters remove or destroy harmful microbes.
Boiling takes care of microbes but won't remove chemical pollutants. Bring the water to a rolling boil for five minutes (or more). Take care not to cross contaminate the boiled water; adding it back to the container used to collect it from the water source negates the effects of boiling.
Excess salt in the body can throw your electrolytes dangerously out of balance, especially if it is consumed on top of dehydration. Sea water may contain pollution and other contaminants of concern as well.
Distill any salt water before you drink it. Bring the water to a boil and collect the water vapor. Distillation removes not only salt but microbes often missed by other purification methods.
Stagnant water provides a better home for parasites and viruses than moving water. Stagnant water allows less common microorganisms to thrive, ones that may cause rare and unusually severe symptoms and effects. Avoid using any isolated or standing pools for drinking, especially if there are dead animals, dead plants or a noticeable lack of plants near the water. Do not drink from pools overgrown with algae or those containing dead fish or animals.
Be aware of areas that may appear to provide potable water but that may contain water contaminated from flood water runoff. Human or animal sewage may have mixed with the water. Depending on the area, industrial and agricultural runoff or waste may also make its way in. Do not use well water if there has been flooding that covered the equipment used to draw the well water or that may have mixed with the well water itself.
Avoid all alcohol consumption, especially in an emergency situation where survival may depend upon possessing all your faculties. Alcohol impairs judgment, memory, reaction time and coordination. Such impairments could lead you to become lost, suffer a fall or to make a poor decision and further compromise your situation.
The effect it has on your mind and body may be amplified if you are already in a dehydrated state. Alcohol worsens dehydration--your body uses water from your tissues to metabolize it.