Do you know what kind of contaminants are in your drinking water and what they can do to your body?
One of them is LEAD and here is a short extract from the World Health Organization:
Young children are particularly vulnerable to the toxic effects of lead and can suffer profound and permanent adverse health effects, particularly affecting the development of the brain and nervous system. Lead also causes long-term harm in adults, including increased risk of high blood pressure and kidney damage.
If you wanted to know more in detail about it, you can read the full article on their website.