ATI was founded in 1986 by Dennis Totzke, Jim Smith, and Bob Janke, three engineers with extensive experience in water/wastewater management and structural engineering. The firm's first office was located in the basement of an office building in Brookfield.

Throughout the years, ATI has developed a comprehensive list of industrial and municipal waste clients and solidified its reputation as a state-of-the-art water/wastewater engineering firm. Nearly 25 years later, ATI has 35 employees between its two offices in Brookfield, Wisconsin (now 10,000 square feet and not in the basement!) and Lake Villa, Illinois, including more than 20 licensed engineers and architects. ATI has been recognized on the Milwaukee Business Journal’s annual Lists of Largest Engineering and Environmental Firms since 2005.