In the given paper the authors consider the technology of water purification with consideration to the recommendations of the World Health Organization (WHO), European Union (EU) and standards of developed countries. Carcinogenic Unit Risk (UR) magnitude for people constantly exposed to the analyzed carcinogens in the course of a lifetime is estimated. The authors calculate and evaluate unique carcinogenic risk as a complementary probability of cancer development during the whole life of CR when introducing EU standards into water purification technology