Survival Tips – Water

Safety Tip   Source
Treat all water of uncertain quality before using it for drinking, food washing or preparation, washing dishes, brushing teeth, or making ice. In addition to having a bad odor and taste, contaminated water can contain microorganisms (germs) that cause diseases such as dysentery, cholera, typhoid, and hepatitis.

After All Water in Your storage is Gone


SODIS Method


Four Steps to Sodis

The SODIS method is very easy to apply: A transparent PET bottle is cleaned with soap. Then, the bottle is filled with water and placed in full sunlight for at least 6 hours. The water has then been disinfected and can be drunk.

Important points to consider when applying the SODIS method


Step 1

Material, colour and shape of the bottle


We recommend using PET bottles in the application of the SODIS method because they are light and do not break. They are also easy to obtain in many regions. However, glass bottles or special bags can also be used. PET bottles are usually labelled as such, but they are not called by the same name in all countries.
Factsheet Glass vs. PET (EN, FR, ES)
Factsheet Bottle vs. Bag (EN, FR, ES)
Factsheet Use of Bags (EN, FR, ES)

The bottles must be transparent and colourless. PET bottles often have a bluish tinge. This is not a problem. Heavily scratched bottles must be replaced.
Factsheet Ageing of bottles (EN, FR, ES)

The bottles must not hold more than 3 litres.
Factsheet Depth of water (EN, FR, ES)

Step 2



If the water is very turbid, the effectiveness of the method is reduced. It is very easy to determine whether the water is sufficiently clear:

The filled PET bottle must be placed on top of a newspaper headline. Now one must look at the bottom of the bottle from the neck at the top and through the water. If the letters of the headline are readable, the water can be used.

If the letters are not readable, the water must be filtered. This test corresponds to a turbidity of 30 NTU.
Factsheet Turbidity (EN, FR, ES)

Step 3 



Cloudiness affects the strength of solar radiation and thus also the effectiveness of the method.

Rule of thumb:

  • If less than half of the sky is clouded over, 6 hours will be enough to completely disinfect the water.
  • If more than half of the sky is covered with clouds, the bottle must be placed in the sun for 2 consecutive days.

Factsheet Cloudiness (EN, FR, ES)



The method does not work satisfactorily during lengthy periods of rain. On these days, we recommend collecting rainwater.

Step 4

Preventing recontamination


The treated water should be kept in the bottle and drunk directly from the bottle, or poured into a cup or glass immediately before it is drunk. In this way, it is possible to prevent the treated water from becoming contaminated again

These instructions are for treating water of uncertain quality in an emergency situation, when no other reliable clean water source is available, or you have used all of your stored water.
How To Treat Water
There are many ways to treat water. None is perfect. Often the best solution is a combination of methods.
Before treating, let any suspended particles settle to the bottom or strain them through coffee filters or layers of clean cloth.
Make sure you have the necessary materials in your disaster supplies kit for the chosen water treatment method.
There are three water treatment methods:
• Boiling
• Chlorination
• Distillation
Boiling is the safest method of treating water. In a large pot or kettle, bring water to a rolling boil for 1 full minute, keeping in mind that some water will evaporate. Let the water cool before drinking. Boiled water will taste better if you put oxygen back into it by pouring the water back and forth between two clean containers. This also will improve the taste of stored water.
You can use household liquid bleach to kill microorganisms. Use only regular household liquid bleach that contains 5.25 to 6.0 percent sodium hypochlorite. Do not use scented bleaches, color safe bleaches, or bleaches with added cleaners. Because the potency of bleach diminishes with time, use bleach from a newly opened or unopened bottle.
Add 16 drops (1/8 teaspoon) of bleach per gallon of water, stir, and let stand for 30 minutes. The water should have a slight bleach odor. If it doesn’t, then repeat the dosage and let stand another 15 minutes. If it still does not smell of chlorine, discard it and find another source of water. Other chemicals, such as iodine or water treatment products sold in camping or surplus stores that do not contain 5.25 to 6.0 percent sodium hypochlorite as the only active ingredient, are not recommended and should not be used.
Water_Purification_Survive_After_Global_Disaster_Dec_2012.pngWhile the two methods described above will kill most microbes in water, distillation will remove microbes (germs) that resist these methods, as well as heavy metals, salts, and most other chemicals.
Distillation involves boiling water and then collecting only the vapor that condenses. The condensed vapor will not include salt or most other impurities. To distill, fill a pot halfway with water. Tie a cup to the handle on the pot’s lid so that the cup will hang right-side-up when the lid is upside-down (make sure the cup is not dangling into the water) and boil the water for 20 minutes. The water that drips from the lid into the cup is distilled.

  1. No comments yet.
  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: