How to Use Bleach to Disinfect Water

Access to safe water is a critical issue in the wake of many natural disasters.

After a hurricane or flood, it’s important to disinfect water if authorities haven’t confirmed your water is safe for drinking, cleaning or bathing.

During and after a disaster, water can become contaminated with microorganisms (bacteria, for example), sewage, agricultural or industrial waste, chemicals and other substances that can cause illness. And it’s not always practical in an emergency situation to boil water for 1 minute to make it safe to drink.

At those times, bleach can be an effective and safe way to disinfect water.

Red Cross volunteers distribute clean-up supplies like bleach following Hurricane Matthew in 2016. Photo by Daniel Cima for the American Red Cross

Tips for using bleach to disinfect water

Here are some things to remember when using Clorox® Regular-Bleach1, Clorox® Regular-Bleach2 or Clorox Germicidal-Bleach to disinfect water:

  • Before adding bleach, remove all suspended material from the water you’ve collected. To do this, let the water sit long enough for any debris to settle to the bottom of the container.
  • Next, decant the clarified but still-contaminated water into a clean container; then add the bleach. Use the following table to determine how much bleach to add — the amount of bleach you use depends on how much water you are treating and which formula of bleach you are using. (Look at your label to find out which bleach formula you have. The subscript number after the name of the bleach indicates the formula.)

Amount of clear water

Amount of Clorox® Regular-Bleach2

Amount of Clorox® Germidical BleachWith Cloromax

Amount of Concentrated Clorox® Germicidal Bleach1

1 quart

2 drops

 2 drops

2 drops

1 gallon

8 drops

8 drops

6 drops

1.5 gallons

12 drops or 1/8 teaspoon

12 drops or 1/8 teaspoon

2 gallons

12 drops or 1/8 teaspoon

 

 

  • 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 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.

Here are some other important things to remember when disinfecting water with bleach.

Additional resources:

To learn more, visit Clorox.com, including The Truth About Bleach page, for valuable information on bleach safety and how to use it to disinfect surfaces and fight mold and mildew

Flood clean-up tips from the Clorox brand, including how to clean mold and mildew and tips to help prevent mosquitoes outside your home

Using Bleach to Prevent Waterborne Illnesses

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