Government of Nepal

Ministry of Water Supply and Sanitation

Nepal Water Supply Corporation

How to Purify Water

Steps

1 .Clean the container in which you're going to hold or store the water.

Use dish soap and water. Rinse thoroughly. After washing the containers, submerge them in a solution of 1 teaspoon of non-scented liquid household chlorine bleach to every quart (or liter) of water (making sure the entire surface of the bottle comes in contact with the solution for a minimum of 15 seconds), then rinse thoroughly with a weaker mixture of bleach and water.

Don't use any container that has had milk or fruit juice in it. Milk protein and fruit sugars remain in the container and can fuel bacterial growth when water is stored. Plastic soda bottles are suitable.

2. Filter water through a clean cloth.

Then allow it to settle for at least 30 minutes and pour off the clear water for purifying. This process of filtering and settling is especially important if you're going to be using chemical purification because disinfectants are less effective in cloudy, murky, or colored water. It is possible to use cotton cloth, such as a clean handkerchief or clean white sock, orsilk (water passes quickly through multiple layers).

One way to set this up is to cut the bottom off of a water or coke bottle. Roll a clean sock up on itself and stuff it down to the neck of the bottle. Pour your water through the filter until it is clear to the eye. If you have a portable water filter, use it. Don't use any container that has had milk or fruit juice in it. Milk protein and fruit sugars remain in the container and can fuel bacterial growth when water is stored. Plastic soda bottles are suitable.

3. Purify the water.

If you can, combine boiling with a chemical disinfection method; the boiling is more thorough, but the chemical method will continue to keep the water safe when it's stored.|

Boiling: This kills most types of disease-causing organisms and is the most recommended purification technique. Boil the water for 1 full minute, then let it cool. Make sure it's a full, rolling boil. If you are more than one mile above sea level, boil for 3 minutes longer.
Commercial tablets: For commercially prepared chlorine or iodine tablets, follow the instructions that come with them. If you don't have instructions, use one tablet for each quart or litre of water to be purified.
Solar Water Disinfection method: Pouring the water into clear plastic PET bottles, and exposing to direct sunlight for at least 6 hours has been shown to be an effective method of disinfecting.

4. Be careful with the cap or lid of the container.

If you're chemically disinfecting water in a canteen or other portable container with a screw-on cap, wait about five minutes after adding the purifying chemical(s), then partially unscrew the cap and shake the container so that some of the water sloshes on the inside of the cap and the threads of the container, then re-tighten the cap and let it sit for the remainder of the time specified above or in the instructions.

Otherwise, there may still be contaminated water in the cap, on the outside of the container's neck, or on the threads.

5. Take care when consuming.

Once the water in a container has been purified, open and close the container carefully. Don't touch the inside or the rim with your fingers, or else the water could become contaminated.

If you're going to drink some, but not all of the water, don't drink directly from the container. Pour it into another container and drink from that. Contact with your lips and mouth can contaminate water that's going to be stored.
If you don't drink the water immediately, write the date on the bottle. Store it in a cool, dark place for up to six months.

Source: www.wikihow.com