Collier County offices will be closed on Monday, May 28 in observation of Memorial Day, honoring those who have died in service of the United States of America.

Purifying Drinking Water

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Unless you are absolutely certain your home water supply is not contaminated by flood water, purify all water before using it for drinking, food preparation, brushing teeth or dish washing. If the water contains sediment or floating material, strain it through a cloth before treating it. Water can be purified by boiling or by chemical treatment.


Boil water at a rolling boil for at least 10 minutes to kill any disease causing bacteria in the water. Add a pinch of salt to each quart of boiled water to improve the taste.

Chemical treatment

If water cannot be boiled, treat it chemically. Two chemicals usually found in the home will purify water: 

  • Chlorine Bleach such as Clorox or Purex. Household bleach is a good disinfectant for water. However, check the label to be sure that the active ingredient is sodium hypochlorite at 5.25%. Do not use bleach which contains detergents!

    Drops of Chlorine per Gallon of Water based on Percent Chlorine
    Percent ChlorineAdd, per Gallon of Water
    1% 40 drops
    4 to 6% 8 drops
    7 to 10% 4 drops
    Unknown 10 drops

    Mix thoroughly into the water. Let it stand for 30 minutes. The water should have a slight chlorine odor. If it doesn't, repeat the dose and let the water stand for an additional 15 minutes.

  • Iodine: Household iodine from the medicine chest of first aid kit will purify water. The iodine should be 2% United States Pharmacopoeia (U. S. P.) strength. Add 20 drops per gallon of clear water, and 40 drops per gallon of cloudy water. Seal the container and let stand for 30 minutes. The water supply will be safe for an indefinite period.

Water Purification Tablets will also purify water. Follow manufacturer's directions. Water purification tablets are available at drug stores and camping supply departments of your local stores.

Centers for Disease Control (CDC): Hurricanes, Your Health and Safety

This information taken from a pamphlet prepared by:

The Collier County Cooperative Extension Service
14700 Immokalee Road
Naples, FL 33964
239 353 4244