One of my tactics for clearing my psoriasis has been to try to eliminate any potential sources of unhealthy chemicals or products that might have been entering my body. I am quite diligent about reading any material that comes into my hands about things that are good and bad for health. I try to maximise the good things and minimise the bad stuff. You cannot do that without knowing which is good and which is bad, as well as what makes them good or bad.
One tends to believe that the water in USA is top class and that in Africa it is very suspect. My experience from living in Cape Town and Virginia Beach has been that the water in Cape Town is probably of more consistent high quality than in Virginia Beach. Here the water taste varies considerably from month to month. Sometimes it tastes muddy and other times it has a strong chlorine taste. I have little confidence in it being free of bad stuff.
We investigated a whole-house filtration system but it was very costly. We tried a small filter that attaches to the outlet of the faucet, which helped but is lacking in the number of heavy metals and other contaminants that it removes. Eventually we changed to an under-sink two-stage filter that removes a wide range of particles, chemicals and heavy metals and I use that for all drinking water, even if it is to be boiled. I think that the only way to get water that is more pure would be to distill it myself or buy distilled water.
Filtering your own domestic water from the city or county water supply is much cheaper than buying bottled water. It also gives more confidence about the source of the water that I am drinking. There have been a few TV programs and reports of investigations into the sources of some of the brands of bottled water sold in stores. Some of them are suspect or are just water bottled by a small supplier from the public water supply and fraudulently sold as spring water.
The other concern is that plasticisers in the plastic containers will contaminate the liquids that they contain, particularly if the bottle is heated in any way. This may be due to the bottle being inside a hot vehicle or lying on your towel on a hot beach. The toxic chemicals will migrate into the liquid that you will drink, which enables those chemicals to enter your digestive system and then every cell in your body. You can keep your bottled liquids cool to prevent this happening but it might be a long journey from the bottling factory to your mouth. If any supplier in that path is less than careful in storing the cases of bottles in cool areas and out of direct sunlight then the chemicals might have been in the liquids for days or weeks before you even buy the bottle.
Heavy metals and toxic chemicals can show in the human body in many different forms, from psoriasis to cancer or Alzheimer's and Parkinson's. There is no guarantee that any person will not contract those conditions anyway but it is worthwhile to minimise the chances by drinking good clean water, without dangerous contaminants.