Is It Safe to Drink the Water?


If you or one of your travel companions has ever gotten a diarrheal illness when traveling, you know it can be three of the most miserable days of your trip and on a 10-day vacation you’ll likely miss out on a lot of fun activities.

If your travel involves some serious hiking, biking, climbing or any significant physical activity then you could also be at risk of some serious dehydration.

Since prevention is ALWAYS better than treatment, Dr. Christopher Gerard offers some ways you can prevent waterborne diseases.


What can I do to avoid a diarrheal illness when traveling?

Dr. Christopher Gerard:  First, you should see a healthcare provider at least 3 months BEFORE traveling for a full travel consultation and review of immunizations. For prevention of waterborne illness you’ll want to specifically check on your hepatitis A and typhoid vaccination status.

Second, use proper hygiene while traveling. Keep your hands and eating utensils clean, ESPECIALLY after using the toilet. Options are soap and water or an alcohol-based rub (as long as no visible contamination is present).

Third, if you’re not peeling it then clean all fruits and vegetables with CLEAN water.


How can I ensure the water I use is clean?

Dr. Gerard:  Getting clean water depends on the circumstances, but there are a number of options worth considering. Possible waterborne pathogens include: bacteria, viruses, protozoa (e.g., giardia) and helminthes (worms). The method you choose may or may not work for each type of pathogen. Options to consider include: water purifiers, boiling (heat), halogenation (iodine, chlorine), and ultraviolet radiation (UVR). Let’s look at each one separately.

Purification via a filter - typically a hand pump - is generally effective at removing bacteria, protozoa, cysts and worms. But, filters can’t be guaranteed to remove viruses as they are just too small. Also, filters can be heavy and if they clog they are useless. If you’re not sure of the integrity of your filter, then put a drop of food coloring in a glass of water and “filter it” – hold the filtered water up against a white piece of paper, if there is any color to the filtered water then the filter needs to be replaced.

Heat. Boiling water is excellent in that it can kill all organisms mentioned above. The time it takes is variable but generally a good 2’ rapid boil will do. Unfortunately, boiling water can be a slow process that uses lots of fuel.

Halogenation (iodine, chlorine), can be effective against viruses and bacteria but its effectiveness against worms and protozoa is limited. Also, cryptosporidium cysts are notoriously resistant to iodine. Iodine can be tricky to use as well and will leave water with a bad taste. Chlorine dioxide might be a better choice in that it does a better job against cryptosporidium and doesn’t taste as bad as iodine.

Ultraviolet radiation (UVR). There are a number of small, handheld devices on the market now that are reasonably priced (e.g. UV “Steripens”). As long as the water is free of particulates then this method will kill viruses, protozoa, bacteria AND cryptosporidium. The key is having clear water – this can be obtained by PRE-filtration, you can often get way with using a t-shirt or bandana for that purpose. For urban international travel this solution can be ideal. For extended travel, you may need backup batteries.


What method do you use to get clean water?

Dr. Gerard:  My preference is UVR. I find their small size and efficacy to be ideal for solo travel and batteries last for hundreds of uses. However, I do carry a backup of chlorine dioxide in case of mechanical failure or dead batteries.


Image of of Dr. Christopher Gerard, primary care and family medicine physician at EvergreenHealth Primary Care Totem Lake in Kirkland, WA.

About Christopher Gerard, MD

Dr. Christopher Gerard is a primary care physician at EvergreenHealth Primary Care Lakeshore Totem Lake in Kirkland, WA.

Read Dr. Gerard's full profile

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