Disinfecting Water with Household Bleach

If you can’t boil water, ordinary household bleach will disinfect it. Use unscented liquid chlorine bleach. Avoid scented, “splash-less” or color-safe products, and check the label: you want the sodium hypochlorite percentage.

How much bleach (CDC table)

For bleach that is 5% to 9% sodium hypochlorite (most regular household bleach):

Amount of clear water	Bleach to add
1 quart or 1 liter	2 drops
1 gallon	8 drops (a little less than ⅛ teaspoon)
5 gallons	40 drops (½ teaspoon)

For bleach that is only 1% sodium hypochlorite, use 10 drops per quart, 40 drops (½ teaspoon) per gallon, or 200 drops (2½ teaspoons) per 5 gallons.

If the water is cloudy, murky, colored or very cold, use double the amount. It is better still to filter or settle it first, as described in how to boil water.

Steps

1. Use a clean dropper or measuring spoon.
2. Add the bleach and stir well.
3. Let it stand at least 30 minutes before drinking.
4. Store it in clean, covered containers.

Limits

• Bleach kills most bacteria and viruses, but tough parasites such as Cryptosporidium resist chlorine. Boiling is more reliable.
• Like boiling, bleach does nothing against fuel, chemicals or radioactive contamination.
• Bleach loses strength as it ages. Rotate your stored bottle, and keep a dropper taped to it.

For storing water in advance, see how much water to store.