Marco Plumbing, 519 Dundas Street East #2, Whitby, ON L1N 2J5, Canada. 905-619-9700. A Marco Plumbing Ltd is a full service plumbing company in Whitby, ON. Serving the GTA and Durham Region, the plumbing company takes pride in providing exceptional customer service and high quality craftsmanship. Marco Fermo founded A Marco Plumbing in 2003.