The use of contaminated water for drinking or in the preparation of food leads to acute and chronic illnesses. This is a widespread problem and a major cause of death in many countries. Many water borne diseases such as diarrhea, cholera, dysentery and many more are dangerous to life if not treated. It is possible to become immune to the bacteria which cause these diseases by drinking contaminated water. However, bacteria levels rise in the body and these bacteria can pose a threat to life in combination with other infections.[5]

There are two stages involved in making contaminated water safe to drink:

1. Filtration - removal of undissolved substances; and
2. Disinfection.

Using a folded cloth for filteration :

The cloth filter was developed in response to widespread cholera in Bangladesh, particularly among those unable to boil or otherwise treat their water. Water treated this way has a reduced pathogen count of almost 99%. Even 99% efficacy may not be good enough on its own, but it is better than no treatment at all.

Method:

Take a (preferably) old, thin, clean, white, cotton cloth (old, but clean dhoti or sari can be used) and fold it in half three times to form eight layers. These eight layers have to be close together and tight to be effective. Tie the eight-layered cloth around the tap, or place over the mouth of the water container and collect water.

Clean your hands and the water-containers before collecting water. Keep the containers well covered. After filtering, wash the cloth with detergent or rinse with filtered water and dry it in the sun to disinfect it. Water collected this way must be consumed within two to three days. One must always handle water with clean hands. In fact, hands should not come in direct contact with water.

The cloth filter is a cost effective and appropriate method for reducing contamination of drinking water. It is easy to maintain and can be used anywhere. Inexpensive cotton cloth or a sari cloth, folded four to eight times, provides a filter of approximately 20 micrometer mesh size. This is small enough to remove all zoo-plankton, most phytoplankton, and all V. cholerae (the germs responsible for cholera) attached to plankton and particulate matter larger than 20 micrometers. When no other option is available, the cloth filter is "better than nothing". Once the water has been filtered, it still needs to be disinfected.

Disinfection involves removing germs through heat (boiling, exposing bottled water to sunlight for six hours), or by adding chemicals . Eight drops of chlorine per gallon (approximately 4 liters) disinfects water in half an hour. Also, iodine tablets are commercially available, and can be used as per instructions.

Please note, in case of water borne diseases like diarrhea and dysentery, one should mix sugar and salt to water and drink frequently to prevent dehydration. Lack of re-hydration in time is often leads to avoidable fatalities. For more information about the cloth filter method, including a scientific study see : [6][7][8]