Mary Holtenwasser was the wife of Otto Holtenwasser. She has never appeared in the show as she died before the series takes place. She was first mentioned in "The Trough". Mary Holtenwasser, was born around the same time as Otto Holtenwasser, 1898, she was around 50 when she died.
- She used to work as a nurse for the U.S. Army.
- She and Otto were the first homeowners in the subdivision.