Background: High concentration of nitrate in drinking water is a problem due to sewage discharge into environment via agricultural activities and urbanization development. If nitrate in drinking water were higher than standard, it will be hazardous for babie. The objective of this research was to determine the nitrate concentration of water in Kashan.

Materials and Methods: This was a descriptive study carried out during 2004-2005. During the study 66 samples were taken from water wells and 288 samples from distribution network. Using spectrophotometer method a spmles were analyzed.

Results: Results of the research showed that the concentration means of nitrate in distribution network was 13.2 (CI: 12.1, 14.4) and 15.4 (CI: 14.2, 16.5) mg/l in winter and summer, respectively. In addition, concentration means of nitrate in water wells was 17.1 (CI: 12.6, 21.5) and 17 (CI: 13, 20.9) mg/l in winter and summer, respectively. Also, in 6 percent of water wells Nitrate was equal to or higher than WHO standard for water quality i.e. 45 mg/l.

Conclusion: Results of this research indicate this research the concentration means of nitrate in water wells and distribution networks were less than 45 mg/l. Because discharge of sewage to absorption well results in high concentration of nitrate of ground water in future, it is recommended to speed up the construction of sewage system of Kashan.