Preparation of Emergency Sources of Potable Water

Public Health and Disease Concerns Related to Coast Guard Operations
Page Navigation
22

will not remove other contaminants such as heavy metals, salts, and most chemicals. Before treating

water, allow suspended particles to settle to the bottom or strain them through a clean cloth.

1. Boiling. Boiling is the safest method of treating water, but is best used for relatively small

quantities of water. Boil water for at least 10 minutes. Some water will evaporate during this

process. Ensure water is cool prior to using.

2. Chlorination using household bleach. Use only regular bleach that contains 5.25% sodium

hypochlorite. Do not use scented, color safe or bleaches with added cleaners. Add 8 drops of

bleach per gallon of water. If the water is cloudy, add 16 drops per gallon. Allow the water to

stand for 30 minutes. A slight, but distinct chlorine smell should be detected after 30 minutes. If

not, repeat the dosage and allow the water to stand for another 30 minutes.

3. Chlorination by Calcium Hypochlorite. Powdered calcium hypochlorite can be used to purify

large quantities of water. Detailed instructions on using calcium hypochlorite can be found in

Chapter 1 of reference (g).