Can someone evaluate my AWA passage

Passage from GMAT:
20. The following appeared in an article in a health and fitness magazine.
“Laboratory studies show that Saluda Natural Spring Water contains several of the minerals necessary for good health and that it is completely free of bacteria. Residents of Saluda, the small town where the water is bottled, are hospitalized less frequently than the national average. Even though Saluda Natural Spring Water may seem expensive, drinking it instead of tap water is a wise investment in good health.”
Discuss how well reasoned... etc.

My response:

The conclusion that though Saluda natural spring water may seem expensive, drinking it instead of tap water is a wise investment in health omits some important considerations that need to be addressed to get a holistic view of the situation under consideration. The argument fails to provide substantive evidence or sound reasoning to be able to prove or even support the conclusion from the given premises. The flaws in the argument include unstated assumptions and extreme generalization of a research. The below passage enumerates the flaws in the argument and remedies to resolve them.

First, the argument readily assumes that the results of the laboratories studies on Saluda Natural Spring Water apply to the water that flows through the entire river. For instance, there could be a situation in which only the area from where the sample has been collected does not contain bacteria, however, there could be areas where the water may be contaminated. Further, the water throughout the river need not possess the same quality as there can be deterioration in quality in the other regions of the river.

Second, the author states that drinking the water from the above stated river is a good choice based on the fact that residents of Saluda are hospitalized less frequently than national average. Author assumes that the residents drink water from the Saluda River. However, such case may not be true in reality. The fact only states that the water is bottled at this area. There is no mention whether the residents actually drink the water from this river.

Further, author fails to take into account that there could be other water with the same or better qualities but not so expensive than the water from the aforesaid river. In such case, clearly, it will be the wise decision to purchase the other water and not the water from the aforesaid river.
Also, the author extrapolates the results from the stated experiment to a general claim. However, this is an unwarranted leap of faith without any substantive evidences.

To remedy the aforesaid flaws, the argument should provide substantive evidences to rule out the other factors that may weaken the author’s claim. Had the argument stated that the sample collected is the apt representative of the entire river and that the residents of the Saluda drink the water from this river and that the results of the sample shall hold true always, then the argument would have provided sound reasoning.

In short, the argument fails to provide compelling reasons to believe in the conclusion that one should investment in drinking the water from the above stated river. Had the argument provided the aforesaid remedies, then the stated conclusion would have become stronger.