Water disinfection is important if authorities haven’t confirmed it is safe to drink, clean with, or bathe in after an emergency, such as a hurricane or flood. During and after a disaster, water can become contaminated with microorganisms (for example, bacteria), sewage, agricultural or industrial waste, chemicals, and other substances that can cause illness1.

Depending on the situation, it’s not always practical in an emergency situation to boil water for 1 minute to make it safe to drink. Here are some things to remember when using Clorox® Regular-Bleach 2 , Clorox® Disinfecting Bleach (Concentrated Formula) or Clorox Germicidal Bleach 4 (Concentrated Formula) for water disinfection:*

Prior to addition of the bleach, it’s important to remove all suspended material from collected water by letting it settle to the bottom or by filtration. This means that after you collect water that hasn’t been treated, you need to filter it through a clean cloth, towel, or coffee filter or let it sit long enough to let any debris settle to the bottom of the container.

Next, decant the clarified contaminated water into a clean container, then add the bleach. Use the following table to determine how much bleach to add — it depends on the type of bleach you have and how much water you are treating.

Allow the treated water to stand for 30 minutes. Properly treated water should have a slight chlorine odor.

If there’s no chlorine odor, then you need to repeat the treatment. Just add the same amount of bleach, and wait for another 15 minutes. Check again for the chlorine odor before drinking the water.

If bleach taste is too strong, pour cleaned water between clean containers several times and let it stand for a few hours before use.

Note that if water is contaminated with a chemical, adding bleach will not make it drinkable.

1. https://www.cdc.gov/disasters/disease/facts.html

* Products are only effective against viruses and bacteria.