General contractingInsights Through generations of hard work, Magnolia Companies has grown into one of Washington DC’s most versatile plumbing and mechanical contractors 29 March 202528 March 2025 Iain Washington DC, Plumbing, Volume 22 Issue 2, Magnolia Companies, John Magnolia, Mechanical 5 min read Founded 75 years ago, Magnolia Companies offers specialist plumbing and mechanical services to clients across.... Read more