ABOUT RAINSOFT Since 1953 RainSoft has focused exclusively on providing the finest whole-house water and air treatment systems for families like yours. RainSoft started with one location in Bensenville, Illinois. Today RainSoft, a division of Aquion Inc., is an international company with dealerships in the United States and 20 other countries. The company headquarters are located in Roselle, Illinois, just outside of Chicago.