Artificially produced deionized (or reverse osmosistreated) water became more extensively used in the supply of drinking water in recent decades. Drinking water manufactured by deionization is stabilized with some minerals, but this is usually not the case with the water deionized as a result of household treatment. Deionized water has poor taste characteristics. This water is highly aggressive and leaches metals and other substances from pipes and associated plumbing materials. Possible adverse health effects of deionized water due to the deficiency of certain important minerals and microelements are described.