I have been reading for last almost 3-4 years about this term "Water Sommelier". There is a website which covers many informative articles on bottled water which is not the thirst quenching water of you & me. The website is finewaters dot com. You can visit the same at your time.
They also offer something called as "Water Sommelier" Courses. After learning one understands what water is & what might be the impurities other stuff. What makes me sick is the etiquette thing they have attached to this. Water, agreed is contaminated at many places. However, to me, at the most, where I am not sure, particularly at unknown places, I take Packaged Drinking Water. Otherwise at home I drink the tap water. And what etiquette? Just with a hand funnel also we take & drink water.
To me, it is unnecessarily hyped profession.Look at an article recently published by a lady water sommelier in India :- https://www.vervemagazine.in/people/a-water-sommelier-wants-to-change-the-way-we-consume-this-overlooked-drink
However, your views are welcome.