In 1875, he was elected on the Democratic ticket a Canal Commissioner.[1] On December 2, 1875, Canal Commissioner Reuben W. Stroud died, and Walrath was appointed to the vacancy, thus anticipating the succession for about a month. The office of Canal Commissioner was abolished by an amendment to the New York State Constitution in 1876, pending the appointment of a Superintendent of Public Works. The Canal Commissioners remained in office until February 8, 1878, when the first Superintendent of Public Works, Benjamin S. W. Clark, qualified to take over the duties from the remaining two Canal Commissioners Walrath and Darius A. Ogden.