Water Purification in Emergency Situations


Water Purification in Emergency Situations: by Senior Police Detective Troy Edwards (Ret), The Crosshairs L.L.C.

I realized that it has been sometime since I have written about water storage or purification.  For the purposes of this article, I am going to concentrate on purification.

Traditionally, water purification is described as the process of “removing undesirable chemicals and/or biological contaminants from contaminated water.” The goal being to produce water fit for a specific purpose in most cases that purpose is human consumption.  Purification can help reduce or even eliminate particles, parasites, bacteria, algae, viruses, fingi, and a range of dissolved and particulate material derived from the surfaces that water may have made contact with after falling as rain.

The treatments that I’m going to cover only work in situations where the water is unsafe because of the presence of bacteria or viruses. If there is a possibility that the water is unsafe because of chemicals, oils, poisonous substances, sewage or other contaminants, do not use the water for drinking.

As most of you know, there are two primary ways to treat water: boiling and adding bleach. If tap water is unsafe because of water contamination such as from floods, streams or lakes, boiling is the best method.  Cloudy water should be filtered before boiling or adding bleach.  There are many ways that you can filter the water.  You can use coffee filters, paper towels, cloths or even a sock or bandanna if in a survival situation.

If you decide to boil water, you must bring the water to a rolling boil for at least one minute.  After you have boiled the water, make sure you let the water cool before drinking.  In most cases, boiling alone should be fine but feel free to also go a step further by adding liquid chlorine bleach.

Now if boiling is not possible, treat water by adding liquid household bleach (the brand does not matter.) Household bleach is typically between 5 percent and 6 percent chlorine. Avoid using bleaches that contain perfumes, dyes and other additives. (Be sure to read the label.)

Place the water in a clean container. Add the amount of bleach according to the table below. Mix thoroughly and allow to sit for at least 30 minutes before using (60 minutes if the water is cloudy or very cold).

Below is the ratio of bleach to water as advised by the D.O.H.:

For 1 quart/1 liter: 3 drops for clear/slightly cloudy water.  5 drops for cloudy or cold water.

For 1/2 gallon/2 qrts/2 liters: 5 drops for clear/slightly cloudy water.  10 drops for cloudy or cold water.

For 1 gallon: 1/8 teaspoon for clear/slightly cloudy water.  1/4 teaspoon for cloudy or cold water.

For 5 gallons: 1/2 teaspoon for clear/slightly cloudy water.  1 teaspoon for cloudy or cold water.

For 10 gallons: 1 teaspoon for clear/slightly cloudy water.  2 teaspoons for cloudy or cold water.

I hope this helps.  Finally, I thought I would leave you with a little blurb on storing water safely.

For emergency storage in a home environment, such as before a natural disaster, a good idea is to store one gallon of water per person per day with at least a three-day supply of water per person.  Collect the water from a safe supply, use thoroughly washed plastic containers such as soft drink bottles or you can also get food-grade plastic buckets or drums. Seal the containers tightly, label each with the date that the water was inserted, and make sure you store them in a cool, dark place. As a matter of maintenance, make sure to replace the water in the containers every six months. Never reuse a container that contained toxic materials such as pesticides, solvents, chemicals, oil or antifreeze!