The water filter industry is largely unregulated, so in many countries it is possible to make significant claims as to the health-giving effects of certain filters which are not supported by science. Also if the relevant technologies are not submitted to any kind of objective testing, it becomes a battle of words between those “with faith” in the products in question and those without faith.
One such range of products is usually referred to as “Alkaline Water”. The claim is made that pure filtered water is “acidic”, Alkaline Water is alkaline, and that for most applications alkaline water is superior to pure filtered water. If water is completely pure, it will not be acidic, it is pH 7 – neutral. However, if there are any impurities in the water then the water will not be pH 7, and pure filtered water is very sensitive to change – even a small amount of carbon dioxide from the air might lower pH significantly, while even a speck of an alkalizing substance such as baking soda will immediately raise the pH to more than 7.
As you can see, H2O has the base level of 7, whereas water with other contaminants in it will not be pH7 – if the contaminants are metals, they are typically positively charged, and will cause the solution to become alkaline, while negatively charged ions such as chlorides, bromides, iodides and the like will cause the solution to become more acidic. The bottom line is that you need to pollute your water if it is pure and you want it to be alkaline (for example).
Check here for further discussion on why these mineral (or other) pollutants are NOT good for you.
For more aggressive “debunking” of the claims around Alkaline Water, check out:
Written by a retired faculty member at the Department of Chemistry, Simon Fraser University
This gives the ruling by the UK’s independent advertising regulator that an advert for alkaline water must not be repeated with claims for health benefits