This book present a result of preliminary radon studies of different water sources from Zaria, Kaduna State-Nigeria. The result of the analysis was based on the internationally accepted procedure and was compared with international standard, the procedure adopted for the analysis was that of American Society for Testing and Material (ASTM 1999). From the data obtained some have exceeded the maximum permissible limit of 11 Bq/L as set by United State Environmental Protection Agency (USEPA) and 10 Bq/L for drinking water set by World Health Organization and adopted by several bodies.