In this study, the performance of one of the most popular household drinking water purification systems (WPS) of Turkey was evaluated. Tap and purified water samples were taken from İpsala District (Thrace Region). A total of 23 significant water quality assessment parameters including essential and toxic metals (pH, TDS, EC, turbidity, Cl, NO3, SO4, PO4, BOD, COD, B, Al, Cr, Mn, Ni, Cu, Zn, As, Sr, Mo, Sb, Ba, Pb) were measured in water samples and how much the WPS improves these parameters were determined. Also Water Quality Index (WQI), Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI), Nutrient Pollution Index (NPI), Cancer Risk (CR), Hazard Quotient (HQ) and Hazard Index (HI) were applied to data in order to assess the qualities of tap and purified water in terms of multiple effects of toxicants and possible risks of human health. As a result of this research, it was determined that the investigated WPS significantly improved the drinking water quality and significantly reduced the scores of applied ecological and health risk assessment indicators.