In the event of a natural disaster or any other type of emergency, clean drinking water may not be available, so it may be necessary to treat water to kill any pathogens that may be lurking in order to prevent yourself or your family from becoming ill. The EPA's current guidelines for treating drinking water in emergencies recommend that chlorine bleach should be added to the water to kill any pathogens that may be contaminating the water. However, a new study has revealed that the recommended doses are not only much higher than necessary, they are also not very practical to carry out. The authors of the study, which was published in Environmental Science & Technology, suggest that the EPA needs to review their current guidelines for treating water in emergency situations, and revise them accordingly.

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When the study was conducted, lead author, Daniele Lantagne, who is now based at Tufts University, was working for the Centers for Disease Control and Prevention (CDC), who funded the research. Lantagne and his co-authors note that following a natural disaster, such as earthquakes, floods or tsunamis, clean water can be hard to come by. Yet people still need to drink water in order to survive. Currently, the EPA recommends that people use the “bottle, boil, bleach” approach to treat water in the event of an emergency if they wish to protect themselves from water-born diseases. This approach implies that people should use bottled water as the first option where possible. If bottled water is not available, they should boil whatever water is available to kill any pathogens. And as a final resort when the first two options are not available (i.e. there is no bottled water, and no electricity or other means of boiling water), people should disinfect water by adding “1/8 teaspoon (or 8 drops) of regular, unscented, liquid household bleach for each gallon of water.” However, the scientists have pointed out that 8 drops does not equate to 1/8 of a teaspoon, and both these amounts are higher than those recommended by the World Health Organization and the Centers for Disease Control and Prevention.

In order to assess the guidelines for water treatment, the researchers tested different concentrations of bleach treatment at six homes across the country, using various sources of water. Their results showed that the range of bleach doses recommended by the EPA (ranging between 8 drops to 1/8 of a teaspoon) were higher than what was needed to kill disease-causing pathogens in the water samples. The authors also note that even if the recommended dosage were lowered, for many of the households they surveyed it would still be impractical to carry out, as none had the type of bleach necessary for safely disinfecting water in the house, and/or they lacked the necessary measuring devices. The scientist thus recommend that the EPA revises it water treatment guidelines and conducts further research into alternative water treatment methods and products that are more practical to carry out in the average household.

To prepare your home in the event of an emergency, we recommend a high quality gravity-fed drinking water filter that does not require electricity and is capable of removing bacteria and viruses, as well as other contaminants that can readily pollute drinking water and pose a risk to your health. This provides a simple, yet effective method of ensuring that you have access to safe drinking water in the event of an emergency.

Journal Reference:

Daniele Lantagne, Bobbie Person, Natalie Smith, Ally Mayer, Kelsey Preston, Elizabeth Blanton, Kristen Jellison. Emergency Water Treatment with Bleach in the United States: The Need to Revise EPA Recommendations. Environmental Science & Technology, 2014; 140409120313005 DOI: 10.1021/es405357y