If humans can maintain a consistent blood pH, then what problems does alkalized water cause us?
Why is it recommended that we filter and boil hard water? Is the issue that hard water can affect the pH of our blood?
Right now, there is no evidence shows hard water can cause any healthy problem.
Previously people were concerned about the high mineral content, such as calcium and magnesium, may cause disease such like cardiovascular disease.
But from the report World Health Organization published in 2003 Hardness in Drinking-water, it says "Although a number of epidemiological studies have shown a statistically significant inverse relationship between the hardness of drinking-water and cardiovascular disease, the available data are inadequate to permit the conclusion that the association is causal. No health-based guideline value for water hardness is proposed."
And the United States National Research Council thinks hard water can supply the calcium and magnesium ions that dietary need. Hard Water Hardness Calcium Magnesium Water Corrosion Mineral Scale
And at the same time, I have to say the filters cannot directly work for hard water because ions cannot be isolate by filter. We can filter the precipitation after boil the water. Boiled water is better because tap water may contain microbes in some country, that will be harm for our health. And also you don't want to feel some "precipitation" while you drinking water. That's it.
For my personal view, I prefer soft water because it tastes a little bit sweet.