Richard Trethewey has been the plumbing and heating expert on the home improvement series This Old House since 1980, after taking over from his father, Ron Trethewey, who was the original expert in the first season. Born and raised in Dedham, Massachusetts, Richard grew up in a family deeply rooted in the plumbing trade—his family business, Trethewey Bros., was founded in 1902. Richard started working in the trade during summers from a young age and is a licensed master and journeyman plumber in Massachusetts. He is well known for his problem-solving approach to plumbing and heating challenges, making complex technical issues understandable for viewers. In addition to his television work, Richard founded RST Thermal, a company that provides training for skilled trades professionals. He remains actively involved in the industry alongside his two sons and enjoys sailing and home renovation. Richard is appreciated for his professionalism, passion for educating homeowners, and his down-to-earth style, which has made him a beloved figure on This Old House and the spinoff Ask This Old House.