Water Quality
The World Health Organization (WHO) attributes 80% of all travel diseases to contaminated drinking water. Don’t let contaminated drinking water spoil your trip. Avoid tap water and ice cubes anytime the water quality is uncertain – even bottled water can be questionable, when available. According to WHO, almost half of all travellers suffer from some form of diarrhoea while en-route.
Water contamination
Drinking water contains three groups of pathogenic microorganisms:
| Family | Known germs | Size range |
| Viruses | Hepatitis A, Norwalk Virus, Rotavirus, Poliovirus | ~0.02 - 0.2 microns |
| Bacteria | E-coli (Escherichia coli), Salmonella (Salmonella typhimurium), Cholera (Vibrio cholerae) | 0.2 - 5 microns |
| Protozoans | Amoeobiasis (Entamoeba histolytica), Giardia lamblia (Giardia intestinalis), Cryptosporidium (Cryptosporidumparvum) | 1 - 15 microns |
Source: Osmonics, Inc.
A large number of additional pathogens are known besides the germs listed above. But according to WHO, their pathogenic (disease-inducing) action is only slight, or they are primarily absorbed along with food.
A large number of additional pathogens are known besides the germs listed above. But according to WHO, their pathogenic (disease-inducing) action is only slight, or they are primarily absorbed along with food.
Viruses
Bacteria
Protozoans
Why treat water?
Because you never know what's in the water, it makes sense to always protect yourself with a quality water system. A pristine stream may be safe one day and contaminated the next. It all depends upon what's happening upstream. Microorganisms generally come from human and animal waste and are spread by rain and run-off. The EPA reports that 90% of the world's fresh water supply is contaminated.
"We highly recommend treating water from every source in the backcountry. You don't know what's upstream - not just people but animals - and you can get infected."
Center for Disease Control and Prevention,
U.S. Government
Hygiene tips for traveling

Fruit that you peel to eat is safe, for example citrus fruit, bananas, pineapples, papayas and mangos.
When travelling to many countries, special precautions should be taken to avoid sickness from microorganisms in food and especially water. Many countries still fertilize with human excrement, making it important to follow a few tips to avoid getting sick.
- Order your drinks without ice, if you are unsure that the ice is germ-free.
- Drink only industrially bottled beverages. “Open” or unsealed bottles could be filled from a contaminated source.
- Order your food well-cooked. Avoid raw or slightly cooked food, seafood, mayonnaise, ice cream, butter, etc.
- Avoid eating food from street vendors.
- Only eat fruits, raw vegetables, or salads if they were washed with germ-free water. Otherwise, you can wash them yourself with disinfected water.
- Avoid raw milk. Pasteurized milk is safe to drink.
- Fruit juices with high sugar content are an ideal medium for bacteria to grow. Only drink fruit juices if the fruit, blender, and anyone’s hands in contact were hygienically cleaned.
- Fresh hot coffee and tea are safe beverages. Beer and wine are also typically safe. Note: Alcoholic beverages do not disinfect bacteria already in the stomach.
- Brush your teeth with germ-free water. Even a small sip of contaminated water can cause diarrhoea.
- Always use germ-free water when taking medicines. Diarrhea is not only uncomfortable; it could also affect the impact of the medicine (i. e. tablets).
- Don’t bathe in tropical surface water.
- Wash your hands regularly, especially after using the toilet and before contact with food.
- Always use clean towels.
