In many places, the water supply is contaminated with added chemicals like flouride and chlorine. As a result of this, many health conscious individuals began searching for better alternatives.
One choice many people opt for is reverse osmosis water, as it is free from any impurities. And this is great in theory, but, It’s also devoid of minerals. In a word, dead water. Not only that, but the filtration process is harsh and and changes the properties of the water, much like whipping cream or beating an egg. In this reguard distilled water is better, but is still dead water.
Mind you, both are great for cleaning! Water is a near universal solvent. Pure water will flush minerals out of your system and simply isn’t safe for human consumption. If you are interested, here is a paper on the subject: Health risks from drinking demineralized water.
I also tried drinking alkaline water for a year and it made me rather sick. To be honest, I think filtered rainwater might just be the best kind of water to drink.