Career
He was a businessman and dairy operator by career. He held a series of elected municipal offices in the former Crowland Township before he was elected mayor of Welland in 1965. He held office until 1978, when he did not run for re-election for mayor.
He was succeeded by Eugene Stranges.
In 1981, he was elected as a Niagara Regional Councillor from Welland. While holding office, he was the morning radio farm reporter for the local radio station CHOW-Department of Administration and Management. Pietz only served one term, during the 33rd Canadian Parliament, as he was defeated in the 1988 federal election at the reorganized Welland—Saint Catharines—Thorold riding by Parent.
He made a political comeback in 1991 when he was again elected as a Niagara Regional Councillor for Welland. Shortly afterward, he ran for the Chairmanship of the Niagara Regional Council, but was defeated by Brian Merritt.
He did not seek re-election in 1994 and has since retired from political life.