In 1972, Edgar Harrell obtained his Masters license. Don Harrell and his father Edgar founded Harrell Plumbing Company, Inc.

Don is the President of the family-owned business and conducts the majority of its work in Bexar and Central/South Texas. In 1977, Don Harrell achieved his Masters license. In 2000, Don received his Masters Med Gas. 

In 2001, Harrell Plumbing, welcomed its' third generation when Don's son, Brad joined the company. Brad received his Masters license 2007 and his Master Med Gas 2010.

In 2003, Don's son, Curtis, joined the company. Curtis his Masters license 2010. In 2011, Don's daughter, Jennifer, joined the company as the Office Administrator.