Household Water Treatment and Safe Storage Factsheet: Source ...

Household Water Treatment and Safe Storage
Fact Sheet: Boiling
The Treatment Process
Potential Treatment Capacity
Very Effective For: Somewhat Effective For: Not Effective For:
Bacteria
Viruses
Protozoa
Helminths
Turbidity
Chemicals
Taste, odour, colour
What is Boiling?
Boiling is considered the world’s oldest,
most common, and one of the most effective
methods for treating water. If done properly,
boiling kills or deactivates all bacteria,
viruses, protozoa (including cysts) and
helminths that cause diarrheal disease.
How Does It Remove Contamination?
Pathogens are killed when the temperature
reaches 100 degrees Celsius.
Operation
Water is heated over a fire or stove until it
boils. Different fuel sources can be used
depending on local availability and cost (e.g.
wood, charcoal, biomass, biogas, kerosene,
propane, solar panels, electricity).
Water bubbling as it boils provides a visual
indicator does away with the need for a
thermometer.
Recommended boiling times varies among
organizations. The World Health
Organization recommends that water be
heated until it reaches the boiling point
(WHO, nd). The Centers for Disease
Control and Prevention, recommends a
rolling boil of 1 minute, to ensure that users
do not stop heating the water before the true
boiling point is reached (CDC, 2009).
CAWST recommends boiling water for 1
minute and adding 1 minute per 1000
metres of elevation.
Recontamination of boiled water is a major
problem. Water is often transferred from the
pot into dirty storage containers which then
make it unsafe to drink. It is recommended
to store boiled water in its pot with a lid to
reduce the risk of recontamination.
Boiled tastes flat to some people. This is
caused by dissolved oxygen escaping from
the water as it boils. The flat taste can be
reduced by vigorously stirring or shaking
cooled water to increase its dissolved
oxygen content.
Boiling water (Credit: Phitar, 2005)