Yesterday I was so unlucky to drink from the tap and felt a lot of ion activity later on. Actualy I never have drunk tap water in Turkey (and also in Russia). It has been rumored to have residual nuclear wastes (still one of the best selling bottled waters in Russia has "Ecologically Pure" sign on its bottles...weird) and so on...but I have seen many households with simple water filter jars and people seem to enjoy it.
A simple search through the net assured that Moscow has one of the best drinkable tap waters in the world. No wonder that it is treated three times with chlorine and once with ozone - imagining what they did to political prisoners 20 years ago, here comes the same attitude to the microbes: KILL'EM ALL!. (A small tip: Chlorine is a gas and it tends to move away from the water as you settle it for some time. That's why glass of still tap water becomes a glass of tonic water in several minutes in Moscow, just add some gin...damn, everything leads to alcoholism in here)
So I have nearly come to a conclusion that it is perfectly safe until I saw this in an article in Moscow Times:
Chlorine is sometimes twice the recommended level, especially when the snow melts in spring and more of the chemical is used to combat the extra pollutants released with meltwater. And the permissible amount of iron in Russia is 300 micrograms per liter, but the level is often higher, and sometimes six or seven times as much. Iron is likely picked up in older pipes.
While these levels are not extreme, Dr. Tarek Sultan of the European Medical Center stressed, drinking a lot of heavily chlorinated water over a long period might "increase your risk factor" of developing cancer. Repeated iron dosing is dangerous mostly for those with diseases such as hemochromatosis, which causes the body to accumulate the metal.
SO that's why all Russians tend to activate the metal detector in the airport. I'd better keep on my ecologically pure bottled water...or I will be licking damp walls for thirst in Guantanamo with my perfect middle eastern outlook and a body full of iron.