NASA Image of Hurricane Sandy, October 30, 2012
Areas of the East coast sustained major damage this week when Hurricane Sandy made a terrifying visit. As residents affected by the Super Storm assess damage and begin to clean up and reconstruct, one critical matter can’t wait: procuring safe drinking water. The US Environmental Protection Agency (EPA) warns that only properly disinfected water should be used for drinking, cooking, making any prepared drink, or for brushing teeth.
Emergency Disinfection of Drinking Water
Municipally Supplied Water: Municipal water supplies serve the majority of US residents. Local governments and health departments are the authoritative source of information on the safety of these supplies. In times of crisis, the public should seek guidance from local authorities who may communicate specific instructions for ensuring drinking water safety.
Private Well Water: Approximately 15 percent of the US population draws its drinking water from private wells, according to EPA. In the wake of significant flooding (during which flood waters covered the base of wells, for example), well owners should test their water and take the necessary steps to disinfect their systems, should that be required. EPA recommends private well owners contact their local or state health department or agricultural extension agent for specific advice.
The following are options based on EPA recommendations for procuring safe drinking water after natural disasters such as Hurricane Sandy:
- Use bottled water: If unopened water bottles have been exposed to flood waters, bottle exteriors should be assumed to be contaminated and should be cleaned and disinfected:
- Clean: Remove all loose dirt and debris from bottle exterior
- Disinfect: Apply a chlorine bleach disinfecting solution (3/4 cup of household liquid bleach to 1 gallon of water) to bottle exterior
Keep bottle exterior wet for 2 minutes, then rinse thoroughly and dry.
Boil water to make it safe: If you have source of heat that you can use safely, boil water vigorously for one minute to kill most types of disease-causing organisms that may be present. (If you live at an altitude greater than one mile, boil for three minutes.)
If your water source is cloudy, filter it through a clean cloth before boiling it. Alternatively, or in addition, allow particles in the water to settle and draw off the water above for boiling, leaving the sediment behind.
Allow water to cool after boiling. Store boiled water in a clean container with a tightly fitted cover. (It is recommended that water be stored in the vessel in which it has been boiled to prevent potential recontamination in transferring it to another container). To improve the flat taste of boiled water, pour it back and forth from one clean container to another and allow it to stand for a few hours, or add a pinch of salt for each quart or liter of water boiled.
If boiling water is not an option, water can be disinfected with household chlorine bleach (label will indicate “5.25 percent available chlorine”). Do not use non-chlorine bleach as it is not approved for emergency water disinfection. Chlorine bleach will kill many types of disease-causing organisms in tainted drinking water. Of all the options listed here, chlorination is the least expensive. It is also the only option that offers a residual level of protection from recontamination as water is stored.
If water is cloudy, before treating it with bleach, filter it through a clean cloth and/or allow particulate matter to settle, drawing off the water above and leaving the sediment behind.
To disinfect water with chlorine bleach, add 1/8 teaspoon (or eight drops) of regular, unscented, liquid household bleach for each gallon of water. Stir well with a clean implement and let water stand for 30 minutes before using. Store disinfected water in a clean container with a tightly fitted cover.
Waterborne illness can represent a significant threat to your family’s health. Some researchers estimate the number of US waterborne disease outbreaks between 1971 and 2002 at approximately 764, resulting in over 575,000 cases of illness and 79 deaths. Other estimates are much higher (see the 2008 study by Reynolds et al., for example). Don’t take a chance when it comes to drinking water!
EPA has further tips on hurricane recovery at: http://www.epa.gov/hurricanes/index.html#recover_hurricane
1The World Health Organization notes pouring water through a clean cotton cloth will remove a certain amount of suspended silt and solids. To prevent introducing contaminants, ensure the same side of the cloth is always facing upwards. The cloth may be cleaned using soap and water.