__NOTOC__[[Image:Ceramic candle filterIcon boiling1.jpg|thumbpng|right|200px80px|Diagram of a ceramic candle filter]][[Image:filter in useboiling water.jpg|thumb|right|250px200px|Man using the ceramic candle filterBoiling water for purification. <br>Photo: [https://kopernik.info/ Kopernick]]]
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. Pathogens are killed when the temperature reaches 100 degrees Celsius. In high-lying areas, where the boiling temperature of water can be as low as 80 degrees Celcius, a longer boiling time is necessary to kill all pathogens.
Organizations recommend boiling both for water treatment in developing countries and to provide safe drinking water in emergency situations throughout the world. Although boiling time recommendations vary significantly, from 0-20 minutes, to make water safe for consumption the water simply must reach the boiling point of 100°C. However, studies in developing countries have documented incomplete inactivation of bacteria in boiled water. This disparity between the laboratory and field results is attributed to users not heating the water to the boiling point and/or recontamination of boiled water in storage. To date, there have been no peer reviewed studies assessing the health impact associated with boiling water, although some case-control studies in cholera outbreaks have noted boiling as being protective against cholera.
===Suitable conditions ===
Boiling is applicable in area with a good fuel supply, a cultural tradition of boiling, and where water is stored safely after boiling.
{{procontable | proborder="1" cellpadding="5" cellspacing="0" align="center"|-! width="50%" style="background:#efefef;" | Advantages! style="background:#f0f8ff;" | Disadvantages|-| valign="top" | - Simple <br>
- Uses common knowledge <br>
- Gernerally uses locally available materials <br>
- Proven inactivation of all bacteria, viruses and protozoa, even in turbid or contaminated water<br>- Socio-cultural acceptance of boiling for water treatment, particularly in tea-consuming cultures<br>- Easy and very effective<br>| convalign= "top" | - Inefficient <br>
- Requires a considerable amount of energy (wood, charcoal, fuel) <br>
- Time consuming<br>
- Does not remove suspended or dissolved compounds <br>
- Lack of residual protection against contamination<br>- Potential for burn injuries<br>- Potentially high cost of carbon-based fuel source (with concurrent deforestation risk) and the opportunity cost of collecting fuel<br>- Potential user taste objections<br>- Potential for incomplete water treatment if users do not bring water to full boiling temperature<br>- Indoor pollution: increased risk of respiratory infections from indoor stoves or fires<br>- After boiling, water needs cooling down (cannot be consumed immediately)<br>- Deforestation (approx. 1 kg wood/1 litre water)<br>- CO2 emission<br>|}}
{{Potential_Treatment_Capacity_table
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===Construction, operations and maintenance=== [[Image:village boiling.jpg|thumb|right|200px|Several solar cookers at work boiling water to make it safe to drink. Photo: [http://climate.nasa.gov/kids/games/solaroven/index.cfm Nasa.gov]]]
====Operation====
Pots used for boiling may need to be replaced.
===Costs===
{{Treatment_Cost
Note: Program, transportation and education costs are not included.
===Manuals, videos, and links===
* [http://www.cawst.org/assets/File/HWTS_Fact_Sheet_Boiling.pdf Household Water Treatment and Safe Storage, Fact Sheet 4.1: BOILING]. Provided by: [http://www.cawst.org CAWST (Centre for Affordable Water and Sanitation Technology)]
==Field experiences=References= ==Reference manuals, videos, and links==[http://www.cawst.org CAWST (Centre for Affordable Water and Sanitation Technology)] ==Acknowledgements== ==Footnotes==
<references/>
===Acknowledgements===
This article is based on a factsheet from [http://www.cawst.org/ Centre for Affordable Water and Sanitation Technology (CAWST)], which is gratefully acknowledged.
*<cite>Household Water Treatment Options in Developing Countries: Boiling. Centers for Disease Control and Prevention (2009). Household Water Treatment Options in Developing Countries: Boiling. Atlanta, USA.</cite>
*<cite id=clasen07>Clasen, T. (2007)[http://citeseerx.ist.psu. edu/viewdoc/download?doi=10.1.1.485.2145&rep=rep1&type=pdf Microbiological effectiveness Effectiveness and cost Cost of boiling to disinfect drinking water: Case studies from Vietnam and Disinfecting Water by Boiling in Semi-urban India]. (Presentation) London School of Hygiene and Tropical Medicine, 2008.</cite>
*<cite id=clasenetal07>Clasen, T., Thao, D., Boisson, S., and Shipin, Oet al. [http://www.ncbi.nlm.nih. (2008) gov/pubmed/18605541 Microbiological effectiveness and cost of boiling to disinfect drinking water in rural Vietnam]. Environmental Science and Technology; 42(12): 42:55.</cite>2008.
*<cite id=WHO>World Health Organization. [http://www.who.int/entity/household_water/resources/emergencies.pdf Household Water Treatment and Safe Storage Following Emergencies and Disasters: South Asia Earthquake and Tsunami]. Available at: [wwwWorld Health Organization.who.int/household_water/en/]</cite>