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Trip planning, disease prevention and sanitation

Dehydration, heat and cold

As we all know, the human body is mostly water. Our need for water is only second to our need for oxygen. While a person can survive for weeks without food, without water death usually occurs within three days.

In temperate zones, average daily fluid loss by an adult is one and a half to two and a half litres as urine, one to two litres as sweat, and one half to one litre as vapour while breathing. In hot and humid conditions, perspiration increases rapidly, and at high altitude vapour loss can exceed five litres per day.

In one case, researchers determined that distance runners lost in excess of three litres per hour of sweat during a race in Rio de Janeiro with a mid-30C temperature and high humidity. Such conditions regularly occur during the summer in the southern US and Europe. Even in the Rockies, Coast Mountains and Cascades of western North America, summer temperatures can exceed 30C.

Carrying a heavy pack up hundreds of vertical metres over 15 kilometres of trail can result in massive fluid loss. Yet, all dangers posed by pathogens or chemical pollutants pale in comparison to dehydration, at least in the short term. Severe fluid loss can cause death in a day or less, in both hot and cold weather, particularly at high altitude. Dark or yellow urine, or volume under a half litre per day, are clear indications of dehydration. The best indicator of proper hydration is about two litres of light yellow or clear urine per day.

Heat Illnesses

In hot weather, without proper hydration, mild dehydration can advance rapidly to heat cramps, heat exhaustion and eventually heat stroke.

Heat cramps are painful knotting or spasms, usually in the abdominal and calf muscles, caused by a depletion of salt and fluid.

Heat exhaustion occurs when body fluid levels are low enough that blood drops in volume and thickens. Blood flow to internal organs, including the brain, decreases as the body directs more blood to the skin in an effort to give off heat and reduce body temperature.

Without immediate treatment, heat exhaustion will lead to heat stroke. At this stage, the body cannot cool itself, sweating stops and body temperature rises causing the brain and internal organs to start failing. The body then slips into a coma and death follows.

Heat Exhaustion

Heat exhaustion is characterized by a slightly elevated body temperature, cool skin that is moist and pale or red, headache, nausea, dizziness, weakness and exhaustion.

A person with symptoms must get into the shade, remove sweat-soaked clothes, pour cool water on the skin and drink fluids. These steps can reverse early symptoms of heat exhaustion. Fanning can increase evaporation and further cool the body.

A conscious casualty may experience vomiting and nausea, which can be minimized by drinking small amounts of water every 15 minutes for several hours. The ill person must stop all activity for the day and rest in a cool place while continuing to take in fluids under the guidance of a companion.

Heat Stroke

Untreated heat exhaustion will progress to heat stroke.

Heat stroke is characterized by high body temperature, skin that is red, hot, and dry, strange or irritable behaviour, eventual loss of consciousness, a weak rapid pulse, and quick shallow breathing.

In the wilderness, beyond the reach of emergency medical services, treatment is difficult and time is critical.

Cool the casualty’s body in any manner possible including wetting with cool water and fanning. However, do not submerge the body in cool water because breathing may stop or the casualty might go into cardiac arrest.

While cooling the casualty, monitor his breathing and heart rate and be prepared to initiate rescue breathing or CPR.

A conscious casualty must drink fluids. In advanced heat stroke, when the casualty is unconscious, death will follow without intravenous replenishment. Only trained medical personnel with the proper equipment should start intravenous hydration.

In most backcountry situations, a casualty must be transported to a hospital within one or two days or death is inevitable.

Preventing Heat Illnesses

The best treatments for heat emergencies are preventative.

Avoid exerting yourself during the heat of the day, slow down as the temperature rises, take breaks in the shade, wear a light-coloured hat and most importantly drink plenty of fluids including water, soup, fruit juices, and sport drinks.

Alcoholic and caffeinated beverages should be avoided because they contain diuretics that promote fluid loss.

While hiking, backpacking, or climbing in warm weather drink a half to one litre of water per hour of activity. In hot weather, when carrying a heavy load, or at altitudes above 4,000 metres drink one litre or more per hour.

If you or a companion experience symptoms of overheating such as heavy sweating and cramping muscles immediately move into the shade, cool off and begin drinking liquids. Stretching and massage can relieve heat-cramped muscles. If cramps vanish and you observe no further signs of illness activity can resume with frequent breaks and regular hydration.

Dehydration and Cold Illnesses

In cold weather, or at altitudes above 4,000 metres, dehydration can occur quickly because of rapid water loss into dry air during breathing.

In cold conditions, dehydration can lead to depression, impaired judgement, physical weakness and lethargy, all inherently dangerous in especially when route finding, in bad weather or while climbing.

Dehydration contributes to hypothermia by reducing blood volume. The smaller flow inhibits heat production from exercise and increases the possibility of frostbite. In severe cases, thickened blood can clot in the body and cause pulmonary embolism, which can kill instantly.


A person who is dehydrated in cold weather, or at high altitude, will likely have a reduced sense of thirst and must be monitored to ensure proper hydration, particularly if they display symptoms of impaired judgement or lethargy.

Preventing dehydration requires a calculated effort to drink at least two litres of water per day in low effort activities such as ice-fishing and up to six litres or more per day when cross-country skiing or climbing at high altitude.

Effective Drinking

Dehydration and related heat and cold illnesses come on rapidly with minimal warning so preventative hydration is absolutely essential. To the contrary, illnesses caused by waterborne pathogens usually require days or weeks of incubation time. In the case of short wilderness adventures, most people are at home long before symptoms start and even then illnesses are rarely life threatening.

Because dehydration and associated illnesses can kill within hours you should rarely hesitate to drink untreated water as a preventive measure. The exceptions are seawater and urine, which actually promote water loss from the body and are worse than not drinking at all or water that is obviously contaminated with chemicals.

Try to drink regularly as you hike, climb, or paddle. Water bottles or bags, which are carried in your pack and allow easy drinking through tubes are excellent for ensuring proper hydration. If you cannot afford to carry the extra weight of water, such as during a rapid summit bid, try guzzling large quantities at every water source and only carry a litre with you.

If you are camping, drinking large quantities before bed is an effective way to rehydrate and prepare for the next day. When you need to get up early for a long hike or summit attempt the bonus of bedtime guzzling is that your bladder works as a water alarm! With some practice, you can learn to how mauch water to dirnk to wake up at a specific time.

Planning and finding water sources

Before heading out for a hike or a weekend of camping you should always consider sources of drinking water.

Many public and private campgrounds in North America, Europe, Australia and New Zealand provide treated drinking water or high-quality well water that is monitored regularly and can be used with confidence. In less accessible recreation areas and may developing countries, treated water is rarely available.

Ensuring access to quality drinking water, or the ability to treat water, is a vital aspect of planning any trip or adventure and planning should be in place before you shoulder the pack or secure the canoe to the roof-rack.

The most important parts of your plan should focus on locating possible sources of both drinking water and potentiall sources of contamination, both microbiological and chemical, and choosing a water treatment system.

Planning for Drinking Water

Plan out the type of trip or adventure you are planning, whether hiking / trekking, backpacking, canoing or skiing, the number of days you will be gone and the number of people in your party.

You should plan to consume two to four litres of water per person per day during any reasonably intense or highly intense activity. Boost your needs to four to six litres in hot weather, at altitude, or if you are carrying a heavy pack.

When car camping or day hiking, you could bring water from home in a clean container, but a long day trip, or overnight excursion into the backcountry, makes this impossible because of the weight—one litre of water has a mass of one kilogram (2.2 pounds).

Tap into Available Knowledge

Consult guidebooks, local health and environmental agencies and local knowledge such as climbing clubs that may be able to tell you about water sources in recreation areas, along popular trails or in huts and at campgrounds.

Look at current topographical maps covering your trip area and identify possible water sources such as lakes, ponds, sink holes, springs, streams, rivers, snow packs and glaciers in the areas where you are going.

Next, look for potential sources of microbiological and chemical contamination. These include towns, cities and areas with agricultural, ranching or industrial activity. Pay attention to natural sources of contamination such as salt flats. Look for small subdivisions, campgrounds, backcountry huts, outhouses, golf courses, oil well heads, landfill sites and other sites of human activity that might leach fertilizer, heavy metals, and microbiological contaminants into groundwater or lakes and streams. Mark these sites on your map so you can avoid drinking water downstream from them.

In the United Kingdom, Ordinance Survey (OS) maps are particualry detailed and show current and often historic farms and industrial areas in popualr walking areas.

If necessary to augment your research or resolve questions, consult your municipal, regional, provincial / state or national government department responsible for the environment and inquire about the water quality in the areas where you are heading. Most provincial and state agencies in North America have extensive information on the impact of human activity and natural phenomena on water quality in their jurisdictions.

Based on your research, carefully mark the best sources of water on your map to ensure the purest possible water. The basic rule is that water flows downhill so generally speaking the higher the elevation the purer the water and upstream of any potential source of contamination is always better than downstream.

Springs or alpine streams drain smaller areas of land and are preferable to rivers because it is easier to assess the quality of the drainage basin. When possible, avoid all water sources from drainages with agricultural (including golf courses), industrial or urban activity.

On Your Trip

When entering parks or recreational areas, ask available staff about water quality and possible sources of contamination and if travelling on private land ask the landowner or farmers.

Once you are actually out in the wilds, avoid localized sources of contamination. As you travel take stock of the terrain. Look for animal or human faeces including cow pies, dead animals, evidence of past industrial activity such as mining or logging, and other sources of contamination not obvious from your maps.

Always strive to select water from the highest quality source. Take water upstream of bridges, campsites, parking lots, out-houses, boat ramps, backcountry huts and hiking trails. Keep in mind that even a high alpine stream can be a source of serious microbiological risk if you draw water directly below a leaking outhouse tucked away in the bushes.

When drawing water from a stream or river, choose a location free from mud or suspended particles where the water is running quickly and is not pooled or stagnant looking.

When drawing from lakes and ponds, take water off the top because many chemicals and heavy metals and most microbiological organisms tend to become highly concentrated in mud and bottom sediment over time. Research shows that bottom sediments can contain 100–1,000 times as many microorganisms as surface water, and sunlight plays an important role in destroying microorganisms near the surface.

Since you can’t see, smell or taste microbiological contaminants or many chemical and elemental contaminants, clear clean looking water may not necessarily be safe. However, the appearance, smell and taste can help in assessing quality when you have no other option.

If water quality is questionable look for clarity, which indicates fewer suspended particles and compounds. Look for natural or unnatural oily substances on the surface visible as a purplish film. Smell the water for sulfur, petroleum, fertilizer or other objectionable odours. While not all bad odours indicate poor water quality, they can be a good indication that something is not right, and drinking stinky water, even if it is harmless, is hardly enjoyable so choose a different source if possible.

Algal Blooms

Avoid any water source with an agal bloom indicated by a green, yellow-brown or red scum on the surface. The phytoplankton that produces the bloom can be in in concentrations of billions of cells per litre of water and can give off dangerous toxins. Furthermore, blooms are usually the result of an abundance of phosphorus and thus indicate potentially high levels of fertilizer contamination.

Disease Prevention and Sanitation

The fact is that humans are guilty of spreading many pathogenic organisms into drinking water sources through poor sanitation practices. While we cannot stop animals from spreading pathogens like Giardia, we can stop ourselves by following these guidelines:

  • When hiking always dispose of your faeces at least 50 metres from any water source. If there is a drop toilet then use it. If not, bury your faeces in a hole 15 centimetres deep in biologically active soil where it will be broken down. Pack out your toilet paper in a sealed container. Other alternatives include smearing your faeces in a thin layer on a sun-exposed rock—well away from the path of other people—so that UV radiation and drying will quickly deactivate potential pathogens. In many crowded recreation areas in the US, people are now required to pack their faeces out in sealed containers for disposal in municipal toilets. This trend will likely increase as more people take to the backcountry and levels of contamination escalate.
  • Urinate at least 50 metres from water sources and on sun-exposed rocks or sand for rapid evaporation. Try to avoid urinating on plants.
  • Wash dishes with biodegradable soap or preferably without soap (try using sand or snow) well away from water sources and then fling gray water from dishes or body washing over a wide area of vegetation at least 50 metres from water sources. This will prevent soap contamination of water sources and keep food particles from becoming nutirents for waterborne bacteria.
  • Practice good hygiene by washing and/or sanitizing your hands away from water sources after urinating or defecating and before cooking or eating. When travelling do the same anytime after riding public transport or touching door handles to prevent the faecal–oral transmission of pathogens.

People with diarrhea or other illnesses should not prepare meals. If someone in your party is sick, wash dishes and utensils with water containing a halogen or boil them to prevent the spread of illness.