William S. Hewett was a major bridge contractor in the Minneapolis area from the 1890s until well into the 20th century.

His firm designed and built a number of bridges for the Twin City Rapid Transit Company when it was electrifying and expanding its system around the turn of the 20th century.

Bridges built by Hewett's firm used included some of the earliest reinforced concrete bridges built using the Melan system invented by Viennese engineer Josef Melan and patented in the United States in 1894.

Hewett probably became familiar with the Melan system when working with his uncle's construction firm in northwest Iowa.

Hewett also built the reinforced concrete Washburn Water Tower in Minneapolis.