Emergency Disinfection of Drinking Water

 

In an emergency situation where regular water service has been interrupted – like a hurricane, flood, or water pipe breakage – local authorities may recommend using only bottled water, boiled water, or disinfected water until regular water service is restored. The instructions below show you how to boil and disinfect water to kill most disease-causing microorganisms that may be present in the water. However, note that boiling or disinfection will not destroy other contaminants, such as heavy metals, salts, and most other chemicals. 

ONLY USE WATER THAT HAS BEEN PROPERLY DISINFECTED FOR DRINKING, COOKING, MAKING ANY PREPARED DRINK, WASHING DISHES AND FOR BRUSHING TEETH.

Tip 1: Use bottled water

Use bottled water or water you have properly prepared and stored as an emergency water supply.



Tip 2: Boil water

Boil water, if you do not have bottled water. Boiling is sufficient to kill pathogenic bacteria, viruses and protozoa (WHO, 2015).If water is cloudy, let it settle and filter it through a clean cloth, towel, or coffee filter.

Bring water to a rolling boil for at least one minute. 

Let water cool naturally and store it in clean containers with covers. 

To improve the flat taste of boiled water, add one pinch of salt to each quart or litre of water, or pour the water from one clean container to another several times.

Tip 3: Disinfect the water

Disinfect water using household bleach, if you can’t boil water. Only use regular, unscented chlorine bleach products that are suitable for disinfection and sanitization as indicated on the label. The label may say that the active ingredient contains 6 or 8.25% of sodium hypochlorite. Do not use scented, color safe, or bleaches with added cleaners.If water is cloudy, let it settle and filter it through a clean cloth, paper towel, or coffee filter.

1. Locate a clean dropper from your medicine cabinet or emergency supply kit.

2. Locate a fresh liquid chlorine bleach or liquid chlorine bleach that is stored at room temperatures for less than one year.

3. Use the table below as a guide to decide the amount of bleach you should add to the water, for example, 8 drops of 6% bleach, or 6 drops of 8.25% bleach, to each gallon of water. Double the amount of bleach if the water is cloudy, colored, or very cold.

4. Stir and let stand for 30 minutes. The water should have a slight chlorine odor. If it doesn’t, repeat the dosage and let stand for another 15 minutes before use.

5. If the chlorine taste is too strong, pour the water from one clean container to another and let it stand for a few hours before use.

Other Disinfection Methods



If you don’t have liquid bleach, you can use one of the other disinfection methods described below:

Common household iodine (or “tincture of iodine”). You may have iodine in your medicine cabinet or first aid kit. Add five drops of 2% tincture of iodine to each quart or liter of water that you are disinfecting. If the water is cloudy or colored, add 10 drops of iodine. Stir and let the water stand for at least 30 minutes before use.

Water disinfection tablets. You can disinfect water with tablets that contain chlorine, iodine, chlorine dioxide, or other disinfecting agents. These tablets are available online or at pharmacies and sporting goods stores. Follow the instructions on the product label as each product may have a different strength.