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Water Safety in Emergencies

Kitchen Faucet - Flickr: Nick HumphriesRoxanne Johnson , Water Quality Associate

Water may not be safe to drink, clean with or bathe in after an emergency, such as a flood. During and after a disaster, water can become contaminated with microorganisms, such as bacteria, sewage, agricultural or industrial waste, chemicals and other substances that can cause illness or death. This fact sheet offers guidance to help you make sure water is safe to use:

  • Listen to and follow public announcements. Local authorities will tell you if tap water is safe to drink or to use for cooking or bathing. If the water is not safe to use, follow local instructions to use bottled water or to boil or disinfect water for cooking, cleaning or bathing.
  • Use only bottled, boiled or treated water for drinking, cooking or preparing food, washing dishes, cleaning, brushing your teeth, washing your hands, making ice and bathing until your water supply is tested and found safe. If your water supply is limited, you can use alcohol-based hand sanitizer for washing your hands.
  • If you use bottled water, be sure it came from a safe source. If you do not know that the water came from a safe source, you should boil or treat it before you use it.
  • Boiling water, when practical, is the preferred way to kill harmful bacteria and parasites. Bringing water to a rolling boil for 1 minute will kill most organisms. Boiling will not remove chemical contaminants. If you suspect or are informed that water is contaminated with chemicals, seek another source of water, such as bottled water.
  • If you can't boil water, treat it with chlorine tablets, iodine tablets or unscented household chlorine bleach (5.25% sodium hypochlorite). If you use chlorine tablets or iodine tablets, follow the directions that come with the tablets. If you use household chlorine bleach, add 1/8 teaspoon (~0.75 milliliter [mL]) of bleach per gallon of water if the water is clear. For cloudy water, add 1/4 teaspoon (~1.50 mL) of bleach per gallon. Mix the solution thoroughly and let it stand for about 30 minutes before using it. Treating water with chlorine tablets, iodine tablets or liquid bleach will not kill many parasitic organisms. Boiling is the best way to kill these organisms.
  • Do not rely on water disinfection methods or devices that have not been recommended or approved by local health authorities. Contact your local health department for advice about water treatment products that are being advertised.
  • Use water storage tanks and other types of containers with caution. For example, fire truck storage tanks and previously used cans or bottles may be contaminated with microbes or chemicals. Water containers should be thoroughly cleaned, then rinsed with a bleach solution before use.
    • Mix soap and clean water in container. Shake or stir to clean inside of container, then rinse.
    • For gallon- or liter-sized containers, add about 1 teaspoon (4.9 mL) household bleach (5.25%) with 1 cup (240 mL) water to make a bleach solution.
    • Cover the container and shake the bleach solution thoroughly, allowing it to contact all inside surfaces. Cover and let stand for 30 minutes, then rinse with clean water.
  • Flooded private water wells will need to be tested and disinfected after flood waters recede. If you suspect that your well may be contaminated, contact your local, state or tribal health department or Extension agent for specific advice.
  • Practice basic hygiene. Wash your hands with soap and bottled water or warm water that has been boiled or disinfected. Wash your hands before preparing food or eating, after toilet use, after participating in clean-up activities, and after handling articles contaminated with floodwater or sewage. Use an alcohol-based hand sanitizer to wash your hands if you have a limited supply of clean water.

Source: Centers for Disease Control Keep Food and Water Safe After a Disaster or Power Outage

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