Editing Water (section)

====For drinking====
{{Main|Drinking water}}
[[File:Humanitarian aid OCPA-2005-10-28-090517a.jpg|thumb|A young girl drinking [[bottled water]]]]
[[File:2006 Global Water Availability.svg|thumb|right|Water availability: the fraction of the population using improved water sources by country]]
[[File:Roadside fresh water outlet from glacier, Nubra, Ladakh.jpg|thumb|Roadside fresh water outlet from glacier, [[Nubra]]]]
The [[human body]] contains from 55% to 78% water, depending on body size.<ref>[http://www.madsci.org/posts/archives/2000-05/958588306.An.r.html "Re: What percentage of the human body is composed of water?"] {{Webarchive|url=https://web.archive.org/web/20071125073713/http://madsci.org/posts/archives/2000-05/958588306.An.r.html |date=25 November 2007 }} Jeffrey Utz, M.D., The MadSci Network</ref>{{user-generated inline|date=November 2022}} To function properly, the body requires between {{convert|1|and|7|L|spell=in}}{{citation needed|date=April 2019}} of water per day to avoid [[dehydration]]; the precise amount depends on the level of activity, temperature, humidity, and other factors. Most of this is ingested through foods or beverages other than drinking straight water. It is not clear how much water intake is needed by healthy people, though the British Dietetic Association advises that 2.5 liters of total water daily is the minimum to maintain proper hydration, including 1.8 liters (6 to 7 glasses) obtained directly from beverages.<ref>{{cite web |url=https://www.bbc.co.uk/health/healthy_living/nutrition/drinks_water.shtml |title=Healthy Water Living |work=BBC Health |access-date=1 February 2007 |url-status=dead |archive-url=https://web.archive.org/web/20070101100025/http://www.bbc.co.uk/health/healthy_living/nutrition/drinks_water.shtml |archive-date=1 January 2007}}</ref> Medical literature favors a lower consumption, typically 1 liter of water for an average male, excluding extra requirements due to fluid loss from exercise or warm weather.<ref name=Rhoades_2003>{{cite book |vauthors=Rhoades RA, Tanner GA |title=Medical Physiology |publisher=Lippincott Williams & Wilkins |edition=2nd |location=Baltimore |year=2003 |isbn=978-0-7817-1936-0 |oclc=50554808 |url=https://archive.org/details/medicalphysiolog0000unse }}</ref>

Healthy kidneys can excrete 0.8 to 1 liter of water per hour, but stress such as exercise can reduce this amount. People can drink far more water than necessary while exercising, putting them at risk of [[water intoxication]] (hyperhydration), which can be fatal.<ref>{{cite journal |author=Noakes TD |author2=Goodwin N |author3=Rayner BL |display-authors=etal |title=Water intoxication: a possible complication during endurance exercise |journal=Medicine and Science in Sports and Exercise |year=1985 |volume=17 |issue=3 |pages=370–375 |pmid=4021781 |doi=10.1249/00005768-198506000-00012|doi-access=free }}</ref><ref>{{cite journal |vauthors=Noakes TD, Goodwin N, Rayner BL, Branken T, Taylor RK |title=Water intoxication: a possible complication during endurance exercise, 1985 |journal=Wilderness and Environmental Medicine |year=2005 |volume=16 |issue=4 |pages=221–227 |pmid=16366205 |doi=10.1580/1080-6032(2005)16[221:WIAPCD]2.0.CO;2|s2cid=28370290 |doi-access= }}</ref> The popular claim that "a person should consume eight glasses of water per day" seems to have no real basis in science.<ref>{{cite journal |title='Drink at least eight glasses of water a day.' Really? Is there scientific evidence for '8 × 8'? |journal=American Journal of Physiology. Regulatory, Integrative and Comparative Physiology |volume=283 |issue=5 |pages=R993–R1004 |doi=10.1152/ajpregu.00365.2002 |pmid=12376390 |year=2002 |last1=Valtin |first1=Heinz |s2cid=2256436 |url=http://pdfs.semanticscholar.org/3595/81eb8fa614a2f8c765dc1d4fed3c0e39ee7e.pdf |archive-url=https://web.archive.org/web/20190222112803/http://pdfs.semanticscholar.org/3595/81eb8fa614a2f8c765dc1d4fed3c0e39ee7e.pdf |url-status=dead |archive-date=22 February 2019 }}</ref> Studies have shown that extra water intake, especially up to {{convert|500|mL}} at mealtime, was associated with weight loss.<ref>{{cite journal |vauthors=Stookey JD, Constant F, Popkin BM, Gardner CD |title=Drinking water is associated with weight loss in overweight dieting women independent of diet and activity |journal=Obesity |volume=16 |issue=11 |pages=2481–2488 |date=November 2008 |pmid=18787524 |doi=10.1038/oby.2008.409|s2cid=24899383 }}</ref><ref>{{cite web |url=https://www.sciencedaily.com/releases/2010/08/100823142929.htm |title=Drink water to curb weight gain? Clinical trial confirms effectiveness of simple appetite control method |date=23 August 2010 |website=Science Daily |access-date=14 May 2017 |archive-url=https://web.archive.org/web/20170707071448/https://www.sciencedaily.com/releases/2010/08/100823142929.htm |archive-date=7 July 2017 |url-status=live}}</ref><ref>{{cite journal |vauthors=Dubnov-Raz G, Constantini NW, Yariv H, Nice S, Shapira N |title=Influence of water drinking on resting energy expenditure in overweight children |journal=International Journal of Obesity |volume=35 |issue=10 |pages=1295–1300 |date=October 2011 |pmid=21750519 |doi=10.1038/ijo.2011.130|s2cid=27561994 |doi-access= }}</ref><ref>{{cite journal |author=Dennis EA |author2=Dengo AL |author3=Comber DL |display-authors=etal |title=Water consumption increases weight loss during a hypocaloric diet intervention in middle-aged and older adults |journal=Obesity |volume=18 |issue=2 |pages=300–307 |date=February 2010 |pmid=19661958 |pmc=2859815 |doi=10.1038/oby.2009.235}}</ref><ref>{{cite journal |vauthors=Vij VA, Joshi AS |title=Effect of 'water induced thermogenesis' on body weight, body mass index and body composition of overweight subjects |journal=Journal of Clinical and Diagnostic Research |volume=7 |issue=9 |pages=1894–1896 |date=September 2013 |pmid=24179891 |pmc=3809630 |doi=10.7860/JCDR/2013/5862.3344}}</ref><ref>{{cite journal |vauthors=Muckelbauer R, Sarganas G, Grüneis A, Müller-Nordhorn J |title=Association between water consumption and body weight outcomes: a systematic review |journal=The American Journal of Clinical Nutrition |volume=98 |issue=2 |pages=282–299 |date=August 2013 |pmid=23803882 |doi=10.3945/ajcn.112.055061|s2cid=12265434 |doi-access=free }}</ref> Adequate fluid intake is helpful in preventing constipation.<ref>[http://www.webmd.com/digestive-disorders/water-a-fluid-way-to-manage-constipation "Water, Constipation, Dehydration, and Other Fluids"]. {{Webarchive|url=https://web.archive.org/web/20150304043454/http://www.webmd.com/digestive-disorders/water-a-fluid-way-to-manage-constipation |date=4 March 2015 }}. ''Science Daily''. Retrieved on 28 September 2015.</ref>

[[File:DIN 4844-2 D-P005.svg|thumb|right|[[Hazard symbol]] for non-potable water]]
An original recommendation for water intake in 1945 by the Food and Nutrition Board of the [[U.S. National Research Council]] read: "An ordinary standard for diverse persons is 1 milliliter for each calorie of food. Most of this quantity is contained in prepared foods."<ref>{{cite book |title=Food and Nutrition Board, National Academy of Sciences. Recommended Dietary Allowances |publisher=National Research Council, Reprint and Circular Series, No. 122 |year=1945 |pages=3–18}}</ref> The latest dietary reference intake report by the U.S. National Research Council in general recommended, based on the median total water intake from US survey data (including food sources): {{convert|3.7|L}} for men and {{convert|2.7|L}} of water total for women, noting that water contained in food provided approximately 19% of total water intake in the survey.<ref>{{Cite book|url=https://www.nap.edu/read/10925/chapter/6|title=4 Water {{!}} Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate |publisher=The National Academies Press|doi=10.17226/10925|year=2005|isbn=978-0-309-09169-5|author1=Institute of Medicine|author2=Food Nutrition Board|author3=Standing Committee on the Scientific Evaluation of Dietary Reference Intakes|author4=Panel on Dietary Reference Intakes for Electrolytes and Water|access-date=11 January 2017|archive-url=https://web.archive.org/web/20170113063638/https://www.nap.edu/read/10925/chapter/6|archive-date=13 January 2017|url-status=live}}</ref>

Specifically, pregnant and breastfeeding women need additional fluids to stay hydrated. The US [[Institute of Medicine]] recommends that, on average, men consume {{convert|3|L}} and women {{convert|2.2|L}}; pregnant women should increase intake to {{convert|2.4|L}} and breastfeeding women should get 3 liters (12 cups), since an especially large amount of fluid is lost during nursing.<ref>{{cite web |url=http://www.mayoclinic.com/health/water/NU00283 |title=Water: How much should you drink every day? |publisher=Mayo Clinic |access-date=25 July 2010 |archive-url=https://web.archive.org/web/20101204012725/http://www.mayoclinic.com/health/water/NU00283 |archive-date=4 December 2010 |url-status=live}}</ref> Also noted is that normally, about 20% of water intake comes from food, while the rest comes from drinking water and beverages ([[Caffeine|caffeinated]] included). Water is excreted from the body in multiple forms; through [[urine]] and [[feces]], through [[sweat]]ing, and by exhalation of water vapor in the breath. With physical exertion and heat exposure, water loss will increase and daily fluid needs may increase as well.

Humans require water with few impurities. Common impurities include metal salts and oxides, including copper, iron, calcium and lead,<ref>''Conquering Chemistry'' (4th ed.), 2008</ref>{{full citation needed|date=November 2022}} and harmful bacteria, such as ''[[Vibrio]]''. Some [[solutes]] are acceptable and even desirable for taste enhancement and to provide needed [[electrolyte]]s.<ref>{{cite book |last1=Maton |first1=Anthea |first2=Jean |last2=Hopkins |first3=Charles William |last3=McLaughlin |first4=Susan |last4=Johnson |first5=Maryanna Quon |last5=Warner |first6=David |last6=LaHart |first7=Jill D. |last7=Wright |title=Human Biology and Health |publisher=Prentice Hall |year=1993 |location=Englewood Cliffs, New Jersey |isbn=978-0-13-981176-0 |oclc=32308337 |url=https://archive.org/details/humanbiologyheal00scho }}</ref>

The single largest (by volume) freshwater resource suitable for drinking is [[Lake Baikal]] in Siberia.<ref>{{cite book |url=https://archive.org/details/bub_gb_ujf0kkNF2H8C |page=[https://archive.org/details/bub_gb_ujf0kkNF2H8C/page/n140 125] |title=Water: a shared responsibility |author=Unesco |publisher=Berghahn Books |year=2006 |isbn=978-1-84545-177-6}}</ref>