Due to the scarcity of water resources and significant population growth, water supply has become a challenge. In such circumstances,efficient and cost-effective technologies such as nanotechnology in water treatment is recommended. The latest in water purification, desalinationsystems, Nano-filtration can bepointed. Nano-filtration separation mechanism of the effect of molecular size, The difference in permeability,and solubility of the feed components and electrical interaction between the membrane and ions are present in the feed.The purpose of this study of Nano-filter system to remove contaminants is challenging.This study, using a Nano-filtration system with a nominal capacity of 300 m³/d and Recovery rate of %60,and activated carbon filtration system and sand filterconsists of three vessel was Molasani Nano-filter water treatment plants in 2013. Experiments using the standard method carried out and the results were analyzed using the Excellsoftware.The results showed that the removal efficiency of the system in EC (%98.47), TDS (%98.45), total hardness (%98.74), calcium (%98.55), magnesium (%99.15), chloride (%96.48), sodium (%96.48) and TOC (%98.57) .Due to the low renal solute dissolved in water and the nutritional value of the elements of water, particularly calcium and magnesium and absorption of these elements of water and nutrients through the body is necessary and the relationship between drinking water hardness and reduced incidence of cardiovascular disease in the community is in the long term this can be a contentious issue.