John Melvin Hartz

John Melvin Hartz passed away in his home on May 20, 2026 in Columbia, SC. John was born July 15, 1943 in Middleton, WI, the only child to Lucille Hartz. John graduated from Edgewood High School in Madison, WI and received his B.S. in Civil Engineering from the American Catholic University in Washington, DC. A lifelong lover of trains and a committed environmentalist, John took a job as a Civil Engineer at the State of Wisconsin’s Dept. of Transportation, where he ultimately specialized in high-speed rail.

John met Mary Ruehle and they were married in 1975 in Madison, WI. They divorced in 1996. They had three beautiful daughters, Nicole, Jennifer, and Rebecca. John was a devoted father and throughout his life, his daughters and their remarkable achievements were his greatest pride and joy.

In 1997, John met Susan Grey when they were both looking for a new partner. Susan brought two adult children of her own to the marriage, Dan and Katia. The loving blended family they created was one of the greatest joys of their shared life. They married in Madison, WI in 1999 and then moved to Columbia, SC.

John was a heartfelt lover of animals and devoted pet parents to many dogs and cats. John was also an active participant in his community as well, volunteering with the Lions Club and as a core member of the Skeptical Science team, a volunteer-based network dedicated to debunking climate change denials.

John is survived by his wife, his three daughters and two step-children plus their spouses, six grandchildren and four cats.

A memorial service was held May 24, 2026 in Columbia, SC. The family suggests you plant a tree in honor of John, which can be done here: https://alivingtribute.org.