Tri-County Trenching Specializes in sewer and septic repairs and new installation. Specializing in Sewer, Septic Repairs and New Installation. Excavation Contractor, Land Preparation and Construction. Family owned and operated since 1955. Fully Licensed Bonded and Insured. Products or Services: Septic Tanks, Cement Septic Tanks, Plastic Septic Tanks, Poly Septic Tank, RV Septic Tank and Class 1 Aerobic Septic Tanks. Tri-County Trenching and Septic Inc. in Bensenville, IL is a private company categorized under Septic Tanks. It was established in 1955 and incorporated in Illinois. Business Categories: Sewer Contractors in Bensenville, IL.