Variations of the Rainwater pH and EC in northwest Turkey Water is the main driving factor for the agricultural production in the arid and semi arid regions of the world. Not only the amount of water is necessary for the crop growth, its quality must be also adequate. For this reason, analysis of chemical composition in rainwater is very important in the arid and semi arid areas. In this study, the pH and Electrical Conductivity (EC) variations have been measured in the semi arid Thrace region, which is located in northwest Turkey and takes an essential part of the agricultural production in Turkey. To analyze the rainwater chemistry, rainwater samples have been collected using specially designed collectors in four different areas in the region between November 2000 and December 2002. The average pH values four all sites were almost 6.