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close this bookFood, Water and Family Health: A Manual for Community Educators (UNDP - WHO, 1994, 108 p.)
close this folderUnit 1: Healthy water and better sanitation
View the documentThe problems we have with water
View the documentWays to keep our water supply safe
View the documentGolden rules for safe water
View the documentImproving our environment ourselves
View the documentThe water committee
View the documentWays to make drinking water safer
View the documentLatrines

Ways to make drinking water safer

“If your water is not clean, boiling and chlorination are the best way to make it safe,” the health worker told us.



“But the Golden Rule about boiling water isn’t clear to some of us. How long do we have to boil water to make it safe?” we asked.

The health worker answered, “In the past we were told to boil water for a long time. Now we know that the germs which cause diarrhoea and other diseases are killed or inactivated by boiling the water strongly for one minute.”

“Then boiling water really isn’t so much trouble,” said one mother.

“No, boiling water is not much trouble,” said the health worker. “But remember that when you have made your water safe, you must keep it safe.”

“After boiling, store water in clean, covered containers, away from dirt and germs. Don’t forget that dirty hands make boiled water dirty again. Use a dipper to take water from the container,” she reminded us.

Most of us now store boiled water in clean, covered containers. Children quickly picked up a catchy tune which some students wrote about keeping hands out of drinking water.

You can pour water from a jug
or dip in with a ladle.
You can store water
in a jerry can,
or inside a gourd.

Dirty hands ruin our water.
Keep your drink clean
with a lid.
Do what you ought to
or you’ll feel very, very sick.


“My sister says that in her village they make their water safe by adding a special chemical,” said a woman whose children had recently been sick after drinking dirty water.

She had been listening carefully to the discussion about ways of making water safe.

“Yes, this is called chlorination. It can be a good way of getting safe water for drinking and washing,” the health worker explained.

“Chlorination is the mixing of a chemical called chlorine with water, in order to disinfect the water.

“Sometimes government authorities chlorinate the water for a whole town or district.

“But it is also possible for people whose water is not safe to chlorinate the water they need.

“Products for chlorinating water are available in nearly every area.

“Sometimes the product is sold or distributed as a powder; sometimes it comes in the form of tablets or drops.

“Whatever kind of product you use, be careful to read the instructions about how to use it.”

The health worker then said that if we were unsure about how to chlorinate water, we could ask for advice from the person in our community who is responsible for water supply and sanitation.


Other ways to make drinking water safer

“What if we cannot find enough fuel to burn to boil our water and we do not have the chemicals we need to chlorinate the water?” asked one woman.

“Water can also be made safer to drink by using a good filtration system, built by the community, such as slow sand filtration,” replied the health worker.

“If our community cannot build this kind of filtration system and boiling or chlorination are not possible, there are some ways of making water safer. These include the “two pots” method and using sunlight.

“It is better to use these other methods than no method at all, but they are not nearly as good as boiling or chlorination.

“We should boil or chlorinate water if it is at all possible, and remember that other methods do not make water completely safe. Also remember that even water which has been made clean can get dirty again.

So always get water from the cleanest possible source, keep it in a clean covered container, and keep hands out of the water.”


Making water safer by filtration

“I have heard that one way of making sure that our families have a supply of safer water is to build a water filter,” said an enthusiastic young man.

“I read a book about water filters,” said one of our community elders.

“It is true that a well-built water filter can make water much cleaner,” said the elder, “but we must remember that if there is cholera in our area only boiling and chlorination are really effective ways of obtaining safe water.”

He then explained how to build a water filter.

· Get a barrel or any other container that is at least 1 metre deep. Remove the top of the container (if it has one). Scrub and clean it inside and outside. Fix a tap to the bottom of the container, if possible by welding. Place the container on bricks or stones so that you can fit a pail or jug underneath the tap to catch the water.


· Next get some round stones, about 2-4 cm in diameter, and place them in the container around the opening where the tap has been put. Place the stones in such a way that the opening to the tap is not blocked off completely.


Now get some gravel or stones about the size and shape of peas (about 0.5-1 cm in diameter). Put a layer of these, 15-20 cm deep, in the bottom of the container so that the stones around the tap inlet are covered.


· Add a layer of fine sand 50 cm deep. You can put flat rocks on top of the sand to stop it from being stirred up in the water.

Keep the filter covered and full of water (up to 2-3 cm from the top). When after 2-4 weeks the water starts to flow slowly the filter needs cleaning. Clean the filter by scraping off the top layer of sand. After four or five cleanings you will need to add more sand. To do this you will need to drain out the water until the water level is 10 cm below the level of the sand.

The old man reminded us that wherever guinea worm (also called dracunculiasis) is a problem the water must first be filtered through a simple linen cloth, or through a special nylon gauze distributed for this purpose. (See the Guinea Worm unit)

Making water safer using two pots

You can make water safer by letting it stand for two days inside a pot.

The two-pot method can provide cleaner water for drinking and cooking, but remember that boiling or chlorination are much better ways to make water safer.


What you need:

Two pots


· First day
Begin by filling a large pot with water. Cover the opening and let it stand for 3 days.

· Second and third days
Dirt and germs in the water will begin to settle at the bottom of the pot.

· Fourth day
Carefully pour or scoop off the clean water at the top of the pot and put it into the second pot. Empty the dirty water onto your garden or at the base of the trees growing near your house. Carefully wash the pot, fill it with water and cover it again.

Remember: If you live in an area where guinea worm is a problem, you must filter the water through linen cloth or fine nylon gauze before pouring it into the pots.

Making water safer using sunlight

“We can use the sun to get rid of harmful germs in our water,” said the school teacher. “This is not the best method of making water safer, but it can be used if no better method is possible,” he told us. Then he explained how the method works.

What you need:

You need colourless or light blue glass or clear plastic containers. You should be able to see through any container you use.



· Remove any labels or paper from bottles. Collect water from the well or source. Fill the bottles with clear water. Cover them to keep dirt and insects out.

· Put the bottles in an open space where the sun can shine on them all day. Spread the containers to keep them from shading one another. The bottles should stay in the sun for at least five hours.

If you need the water as soon as possible, a couple of hours in the middle of the day when the sun is strongest will be make the water safer for drinking.

· Use the water which has been cleaned by the sun straight away - if you leave it to stand around, the germs could come back.

Remember: You cannot use this method on cloudy days. Whenever possible, boiling or chlorination are much better methods of making water safer.