The site now occupied by the Commercial State Bank building originally held a rock residence and Theodore Ruch's family butcher shop, a meat market operated in the 1880s by Theodore, George, and Anthony Ruch. The Commercial State Bank of Waterloo was organized as a private bank in 1882 and first operated in the Ruch building on Mill Street. After Theodore Ruch died, his son Thomas sold that building to Hugh Murphy, a co-founder and vice president of the bank, in 1919. The bank became a state bank in July 1920 after Illinois abolished private banks, and on October 1, 1920, it bought this property from Murphy for $5,100. The rock residence was demolished, and the present building was completed in 1929, when the bank moved all operations there. The original two-story structure had five east windows and six north windows on the top floor, and despite later remodeling, the eagle atop the building facing east remained a constant. The second floor once housed offices for Dr. Werth, Dr. Holtz, and an attorney. Before the bank expanded west to the alley in 1989, the Mill Street section resembled a strip mall and included Orrell's Barber Shop, the Twin Shop, Kipping's Dairy Bar, later Ione's Dairy Bar, also known as Sealtest Ice Cream, Gem Dry Cleaners, Clara and Tillie Siegel's Ladies wear, The Waterloo Times, Tony Floerke's Shoe Repair, and other changing businesses. In 1966, a natural gas leak on the north side of Mill Street caused a major explosion that burned down three buildings, damaged many others, and shattered windows along Mill Street, though businesses on the south side suffered limited destruction and resumed operations the next month. The bank continued until it was bought by Midland States Bank in 2008, and that bank closed this location in March 2017. Thor Lohrberg purchased the property in July 2018, and after remodeling, The Vaults Workplace, a co-working center, opened in 2019.