Though I have written similar arguments like this before, it bears repeating here:
Water utilities could provide nearly perfect water to everyone. It would have a reverse osmosis filter right there at the home, it would remineralize the water with the minerals stripped by the RO process, and it would be perfect. It would also cost far more than our society can afford to pay.
The quality of water filtration and the sanitation of the distribution system is ultimately a political decision. There are guidelines, standards, and regulations for water quality, methods of filtration, and delivery. They are very conservative, but we’re always discovering new features. But establishing a policy for how much we spend to remove what contaminants is still ultimately a political decision.
It is also worth pointing out that most contaminants are no longer toxic below a certain level. So you can read about chromium concentrations being measured in single digit parts per billion and you can relax. Some contaminants do not have a lower limit because there simply isn’t any commonly acknowledged research to support what a lower limit might be. An example of this is Hexavalent Chromium (yes, the same stuff that Erin Brockovich became famous for). We presume that there must be a lower limit beyond which its toxicity is no longer an issue, but we don’t have the research or policies to suggest what that level might be.
What we can not tolerate are the ignorant assertions that all contaminants MUST BE ELIMINATED! We can’t afford that as a society. If it matters that much to you, go get your own RO system and remineralize your own water. Note: RO systems strip everything from the water, including essential salts and minerals. Without those minerals, the water will taste terrible, it will strip those salts and minerals from those who drink it, and it could actually lead to serious injury.
This is basic risk management. And we’re doing it by political means. There are technical discussions on how we can remove some of these contaminants and whether those methods are safe enough to use without incurring other problems or expenses.
Finally, I’ll leave you with this: The cause of Flint Michigan’s water problems was something that no registered professional engineer should have signed off on. None of the people who perpetrated that water fiasco were engineers. They didn’t consult with an engineering firm either. They just went ahead and chose the cheapest coagulant they could get their hands on. They didn’t insert a phosphate agent (such as orthophosphate) to coat the distribution pipes. And they didn’t even attempt to control the pH of the water. So when it hit the distribution system, it immediately stripped all the contaminants from the pipes, including lead.
At the water utility where I worked for over 30 years, we used to have a saying: “They were saving money at any cost.” Finally, beware of bottled water. It isn’t as pure as it might first seem. If you’re worried about water quality, invest in a decent water filter. It’s a lot cheaper and far more effective.