Expert: Henry Boyter - 10/26/2006

Question
I mentioned to someone that water is slightly acidic, and this is why I can't drink a lot of it without making my stomach burn. Also this is why it burns when you get water on a small cut, etc. Was I right? Thanks, Bob.

Answer
Had to think how to explain this.  

Water is so slightly acidic as compared to your stomach acid (pH=2), the acidity of the water is not causing stomach burn.  Anything else that people commonly drink are many, many times more acidic than water.  Now there are medical conditions I believe that when liquid is added to the stomach, the stomach is triggered to produce more acid itself, causing the burn.  Talk to your doctor about your situation.

On the cut, it is not the acidity of the water, but the other things found in the water such as salts or salts from the skin washed into the cut that cause the burn.  The water itself will trigger nerve endings to trigger, but the acidity is not really the cause.

The acidity of water, unless from an unusual source (bad well) is so small that it is even hard to measure.  Most water will have a pH that is slightly acidic, but it takes so little base to neutralize it, it is not even counted when doing lab calculations.  The pH found in water is caused by carbon dioxide from the air that dissolves in it.
For details see,

http://www.chem.usu.edu/~sbialkow/Classes/3650/Carbonate/Carbonic%20Acid.html

Sorry you didn't get a confirmation to your suspicions.