However, unlike purified "drinking water," municipal tap water is usually bad for us because it tends to have chlorine and flouride added. Chlorine is toxic and denatures vitamins in our bodies, rendering them useless. Drinking chlorinated water can cause vitamin deficiency.

While flouride helps the teeth, it harms the body. Municipal water also tends to supply toxic impurities such as pesticides and heavy metals which can impair fertility and worsen health. So unless your city’s tap water comes from an aquifer or spring, it is probably not good for you. More info on how city tap water compares to bottled water below.

Rural well water, or water from a small town or nature preserve out in the boonies, is usually relatively unpolluted and won’t contain much but the odd pesticide from local farms, unless it is an old mining town. Mining pollutes big time.

If you are in a city and don’t have a spring near you, then "purified water" is better for the environment and your pocketbook than spring water such as Fiji or Perrier, etc.

The recent study which supposedly showed Fiji water to be of poorer quality than most tap water defined high quality water as water which supplies trace minerals. Fiji water contains nearly no minerals so they defined it as "low quality."

Tap water usually does supply minerals. However, I would say that defining water as "high quality" based solely on mineral content is biased since it misses a *very* important factor: The levels of toxins in the water!! If you analyse the water primarily for toxin levels, Fiji water is of much higher quality than most municipal tap water sources.

So if you live somewhere that spring water is abundant and doesn’t have to be shipped in any further than purified water, then the spring water may be a better choice.

In some cities like Austin TX, San Marcos TX, or Hot Springs Arkansas, you can just go collect your own spring water from a public spring!

And if your city draws its water from a spring’s underground equivalent (aquifer water), like San Antonio TX does, then tap water in such a city will be identical to bottled spring water, and buying spring water will waste money, gasoline and plastic!

You can get the same minerals that spring water supplies by adding a mineral supplement such as coral calcium, or adding more fruits, veggies, beans, nuts and seeds to your diet.

And you can remove chlorine and pesticides from city water by using a filter such as Brita or PUR.
References :
My mother in law, a retired biochemist living in TX. She will not drink city tap water without putting it through a PUR filter, unless she’s in San Antonio!
Also my wife, who is a nurse.

so why is the water bad?
taste?
chemicals that they cannot filter out?
maybe there is another solution.
References :

The spring water may be "fresh" right from a spring, but it also has not been treated to remove potentially harmful content. Also, if has to be shipped further to get to you (that’s not very good for the environment is it? What is not good for the environment is not good for you!). Maybe the book is suggesting that there are helpful natural minerals you can get from the water, but it is better to get them from a more reliable source (like fruits, vegetables, beans, whole grains, unprocessed foods, table salt, and healthy meats and dairy products). "Spring" waters like Fiji have been found to be of a poorer quality than most tap water in the U.S. (this was a recent study that dealt with many different water brands, but targeted Fiji because it is so expensive and has a very low "quality").

"Drinking water" has been through a filtering or purification process of some sort to get to you, and generally travels less of a distance, which is slightly better for the environment. So, they take out the bad stuff and put less bad stuff in the air - better for you if you ask me!

I’d say to forget this trivial idea of the book and examine if the book is telling you to do anything else nonsensical.
References :