Drinking water – how to make it safe when the tap is not

Drinking water in South Africa is regulated against a national standard, and in most municipalities most of the time it meets it. The situations to be careful about are specific rather than constant.

• After a supply interruption or a burst main — pressure loss can draw contamination into the pipes.
• When the water is discoloured, cloudy, or smells or tastes unusual.
• When your municipality has issued a boil-water notice. Take these seriously and follow them until they are lifted.
• Water from a river, dam, borehole, spring or rainwater tank, none of which is treated.
• During or after flooding, when sewage and surface water mix.

Boiling is the most reliable method and needs nothing you do not already have.

1. 1Boiling — bring to a rolling boil for one minute, then let it cool covered. This kills bacteria, viruses and parasites.
2. 2Household bleach — for water you cannot boil, unscented bleach can be used. Follow the dosing on a municipal or health department notice rather than guessing, let it stand for at least half an hour, and expect a faint chlorine smell. Never use scented, thickened or colour-safe bleach.
3. 3Filter first if it is cloudy — pour through a clean cloth or let it settle, because particles shield organisms from both boiling and chlorine.
4. 4Water purification tablets, which are sold for camping and work well when used as directed.
5. 5Store treated water in a clean, covered container and pour rather than dipping a cup or hand into it.

Neither boiling nor bleach removes chemical contamination — from mining, industry or agricultural run-off. If that is the concern, use another source rather than treating it.

• Store water before you need it: a few days' worth for drinking and cooking, in clean sealed containers.
• Keep drinking water separate from washing water, and label containers.
• Use treated or bottled water for brushing teeth, washing salad vegetables and making ice, as well as for drinking.
• Hand hygiene matters more, not less, during an outage — hand sanitiser is a reasonable stand-in when there is no water to wash with.
• Water tankers are treated at source but the containers people carry them in often are not. Wash and rinse yours.

Water-borne illness usually shows up as diarrhoea and vomiting. The treatment is rehydration, and the danger is dehydration rather than the infection itself — particularly in small children and older adults.

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