Salaamun alaykum
It is amazing that so many people believe that Zam Zam water has a Miraculous Healing Power in It.
the First Time I went to Mecca in 1994 , I too, believed in the Magical Zam Zam . At the time I was abusing chemical substances and my Folks being a Good Sunni ( wahabi ) family with good Intentions, decided to take me along to the Holy land in Order to Cure me from My addiction . They firmly believed that, a Dayly Diet of Zam Zam Water and dates as well some Roasted camel meat will do the Trick

.
Anyway , prior to leaving for Jeddah , I was prescribed Rohypnol Tablets to help me cope with the Withdrawal Symptoms and my physician advised me to take it with me where-ever I go ( good advice ) . Unfortunately, one of my brothers who came with us , Talked me out of Taking any Medication to Mecca as he Believes 100% that I would be cured just by being in the
Holy Land and by Drinking Zam Zam Water every day 
To cut the story short, It was to no avail, we spent 42 days in Mecca and Medina , 16 days of that I spent in the hospital with IntraVenous Tubes stuck up both arms plus heart monitor . so much for the Zam Zam Magic

As Brother Tanveer pointed out, Zam Zam water is From Reverse Osmosis and it has a distinc taste which to me felt like the After taste clinging to the roof of the mouth . eventhough took many showers at the Zam Zam water Depot, I did not get Cured from my then addiction . But at least that experience lead me to God only / Quran Muslim. The water obtained through Reverse Osmosis then allowed the
Unsuspecting Muslims to believe That IT is a Special water, imho it is
a Crime. Unfortunately, the Saudis kept silence when it comes to Miraculous Zam Zam water .
Instead of Informing the Ummah that Zam zam is just a water like any other, the Saudis allowed this Deception to continue by their silence.
I have since gone back to Mecca and Medina as an Individual Hajj just to Verify what I had learnt from the Quran regarding haj and Kaaba in 1994. also found out about The Reverse Osmosis Water . friends who have been living in Saudi informed that there are to Kinds of Desalinated Water, The One we Use for Ablution, bath etc which is a direct Desalinated Sea Water , whilst the other Is the Zam Zam which is also Desalinated Sea Water but Put Back into the Underground Reservoirs and Drawn back Up on the First In First out Basis . Hope this Helps.
Cheers
almarh0m.