Note: non-potable in this use means “not known to be safe for direct consumption.” This might be city water from non-approved sources, natural running sources, etc. Water that is contaminated by other matter (radioactive, heavy metals, chemicals) should not be used.
All waterborne enteric pathogens are quickly killed above 60°C (140°F), therefore, although boiling is not necessary to make the water safe to drink, the time taken to heat the water to boiling is usually sufficient to reduce pathogens to safe levels. Allowing the boiled water to cool slowly will also extend the exposure of waterborne enteric pathogens to lethal temperatures.2)