# Can a human survive on brackish water?

**URL:** <https://boards.straightdope.com/t/can-a-human-survive-on-brackish-water/573889>\
**Category:** Factual Questions\
**Created:** [March 8, 2011, 4:10am UTC](https://boards.straightdope.com/t/can-a-human-survive-on-brackish-water/573889 "2011-03-08T04:10:27Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\
**Post date:** [March 8, 2011, 4:10am UTC](https://boards.straightdope.com/t/can-a-human-survive-on-brackish-water/573889/1 "2011-03-08T04:10:27Z")

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The Baltic Sea’s water at the surface, in the middle, has salinity of 6% to 8%, compared to the oceanic average of about 35%. If you were adrift in the Baltic Sea, could you survive by drinking the water? ISTR reading in a book or seeing in a documentary of an RAF study that showed downed fliers could extend their water supply by mixing in up to 50% sea water. (Sorry, no cite.)

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**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\
**Post date:** [March 8, 2011, 4:42am UTC](https://boards.straightdope.com/t/can-a-human-survive-on-brackish-water/573889/2 "2011-03-08T04:42:14Z")

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[Here’s](http://www.redbackdrilling.com.au/Water_quality_guidelines.htm) a chart of guidelines for salinity:

0-800mS/cm  
Good drinking water for humans (provided there is no organic pollution and not too much suspended clay material)

800-2,500  
Can be consumed by humans although most would prefer water in the lower half of this range if possible

2,500-10,000  
Not recommended for human consumption, although water up to 3000mS/cm could be drunk if nothing else was available

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**Author:** ![Sigene](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@Sigene](https://boards.straightdope.com/u/Sigene)\
**Post date:** [March 8, 2011, 5:34pm UTC](https://boards.straightdope.com/t/can-a-human-survive-on-brackish-water/573889/3 "2011-03-08T17:34:30Z")

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> [@Johnny\_L.A](#):
>
> The Baltic Sea’s water at the surface, in the middle, has salinity of 6% to 8%, compared to the oceanic average of about 35%. If you were adrift in the Baltic Sea, could you survive by drinking the water? ISTR reading in a book or seeing in a documentary of an RAF study that showed downed fliers could extend their water supply by mixing in up to 50% sea water. (Sorry, no cite.)

Can you provide a cite for where you got 35% salinity? That can’t possibly be 35% salt. Unless I misunderstand the definition of salinity.

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**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\
**Post date:** [March 8, 2011, 5:51pm UTC](https://boards.straightdope.com/t/can-a-human-survive-on-brackish-water/573889/4 "2011-03-08T17:51:05Z")

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Sorry, I was dead-tired last night and I mis-read. Searching now, it looks like it’s 35 parts per thousand, or 3.5%

Here’s what I read on [Wiki](http://en.wikipedia.org/wiki/Baltic_Sea#Salinity):

> [@](#):
>
> The Baltic Sea’s salinity is much lower than that of ocean water (which averages 35‰)… The open surface waters of the central basin have salinity of 6 to 8 ‰.