Contaminated Water and Diarrhea;
Best Avoidance Measures

Contaminated water is one of the most common causes of diarrhea, especially when you are traveling in developing countries. Not surprisingly, this is often referred to as traveler's diarrhea.

In fact eighty-eight percent of diarrhea cases worldwide are linked to unsafe water. This accounts for 14,000 deaths each day.

You may be surprised to know however, that there are often overlooked sources of unsafe water in developed countries.

Let’s take a look at why unsafe water is one of the major diarrhea causes. Contaminated water as well as contaminated foods can transmit parasites and bacteria into your system.

Contaminated Water - Glass of water half brown

Cryptosporidium and Giardia lamblia are the common diarrhea-causing parasites and Salmonella, Shigella, Campylobacter, Norovirus and Escherichia coli are common diarrhea causing bugs. See this article about green diarrhea for more about how to recognize Giardiasis.

Drinking Water

Public drinking water in developed countries is generally safe but if you want to avoid tummy trouble when traveling always check the advice for the area you are traveling to before drinking the water, having ice cubes in drinks or using it to clean your teeth.

If the water is not to be trusted locally, then choose branded drinks such as sodas and bottled water but always check that they are properly sealed, as tampering and replacement with a cheaper alternative can occur.

Be aware that levels of bacteria will rise in water that gets warm. Do not drink water from a bottle that has been left in a hot car for example. (Not to mention the chemicals that might leach from the plastic into the water)

Drinking Fountains

Although public drinking fountains are less common than they once were they still do exist, especially in schools. Some studies have found that they can be contaminated with Rotavirus a common cause of diarrhea in children. Make sure if you or your children use these that they are regularly cleaned with chlorine bleach and that the water pressure is sufficient to prevent back-siphonage.

Water Purification

Sometimes it can be difficult to get access to safe water, such as when camping or traveling in remote areas. In these cases it is a good idea to know how to purify the water available to you.

The three main methods are:

  • Boiling - Water should be boiled for a minimum of one minute or three minutes at higher altitudes.
  • Halogens - Chlorine dioxide tablets or drops are the best as they will kill bacteria, viruses and parasites. Iodine is no longer recommended for this purpose.
  • Filtration - Filtration is good for removing particles from brackish water. Filters can be purchased in advance of traveling but the water must be boiled or chemically treated afterwards.

Contaminated Water - Recreational Water Illnesses

Illnesses contracted whilst using water for recreational purposes are caused by ingesting, breathing in or being in contact with contaminated water and can include rashes, respiratory problems and wound infections but the commonest problem is diarrhea.

This most often happens when bathing in lakes, oceans, rivers or other polluted water sources.

Did you know that in the United States 45% of assessed streams, 47% of assessed lakes and 32% of assessed estuaries and bays are classified as polluted?

In the U.K. although pollution of waterways has generally been improving since the 1990s, recently there has been a spate of contaminations, especially from farms leaking silage into nearby rivers.

Be aware that splashing in that idyllic stream or swimming in that beautiful lake might give you more than you bargained for!

Other sources of contaminated water can be swimming pools, hot tubs, jacuzzis, waterparks, spas, fountains, and feature sprays if they are not well maintained.

Contaminated Water in
Swimming Pools, Water-parks, Spas

Normally the water in public swimming pools and waterparks is treated with chlorine and should be safe but a recent study by the Center for Disease Control and Prevention found that of 161 samples taken from public swimming pools, private clubs and water parks in the Greater Atlanta area 58% contained E. coli which can potentially cause diarrhea.

Contaminated Water - Swimming Pool

On a good note none of the samples contained the dangerous strain E. coli 0157:H7. Bacteria gets into the water because each person has an average of 0.14 grams of fecal matter on the skin of their peri-anal area and sometimes accidents happen especially if babies are bathing.

Make sure that you take a shower before using a public swimming facility and never swim if you have been suffering from diarrhea.

Make sure that children and babies who are swimming are clean and take them for frequent bathroom breaks.

Do not pee in the pool as the urine (and sweat) can bind with the chlorine and make it less effective.

Owners of private swimming pools should be careful to test and maintain them regularly.

Contaminated Water in Hot Tubs

Hot tubs are particularly likely to harbor bacteria as the elevated temperature of the water encourages growth and the chlorine evaporates more easily thereby losing its efficacy.

Owners of hot tubs have to be especially careful to disinfect the tub regularly, top up the chlorine and test the pH which should optimally be 7.2 as this is the pH at which chlorine is the most effective. They should also encourage soapy showers before use and discourage use by babies and toddlers.

Parasites can live longer than bacteria in these conditions and are not killed easily by chlorine. Cryptosporidiosis is highly resistant to chlorine and will live for days even in well treated water.

People who regularly swim in untreated water, international travelers and people who work with infected cattle are more likely to be carriers of this parasite.


Feature sprays often use water which comes from a reservoir underneath, which is constantly recycled. If this water is not checked and kept clean problems can ensue.


The water in fountains is not usually treated but on a hot day or during celebrations it can be tempting to children and young people. This can include babies wearing diapers/nappies leading to water contamination. You have been warned!

Separating Waste Water and Drinking Water

This may seem obvious to say but waste water and drinking water should be kept completely separate. In developed countries the plumber has normally taken care of this for us but many people in other parts of the world do not have this luxury and so contaminated water is far more common.

For example an estimated 700 million Indians do not have access to a proper toilet. Open defecation (defecating/having a bowel movement wherever the person happens to be) is practiced by 1.1 billion people or 15% of the world’s population.

However, good progress is being made through CATS, Community Approaches to Total Sanitation, now being supported by UNICEF in 50 countries. People are finding their own solutions to separate sanitation and drinking water.

If you are trekking and camping follow this principal too. Dig latrines well away from any water sources.

When I lived in France you would never find a toilet in a bathroom as they consider it unhygienic. It was always in a separate room. The problem was that the separate room did not usually have washing facilities so you had to leave, contaminating the door handle en route and go to the bathroom or kitchen to wash your hands!

Flood Water

Be aware that drinking water can easily become contaminated with human and animal waste during flood conditions. If you should be unfortunate enough to suffer from flooding then drink only bottled or boiled water and wash thoroughly after coming into contact with the flood water.

Enjoy Yourself

Do not let the information in this article put you off traveling or enjoying yourself but use it to be informed about the possible dangers of unsafe water and guard against them. If you have any suggestions for more information on the subject of contaminated water or for the website please do contact me.

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