The agency has been asked to launch a new TV ad, digital banners and online content as the East Yorkshire-based brand seeks to "emotionally" broaden its appeal.
Ben Padley, VictoriaPlumb.com’s chief marketing officer, said: "With the ambitious plans we have for VictoriaPlumb.com, we needed an agency with creative flair and expertise across traditional and new media.
"The Alpha Century team has quickly demonstrated it has the smarts and the imagination to take us to the next level – and beyond."
Alpha Century was launched in 2013 by Hugo Feiler, a former managing director of Grey London, and Barnaby Girling, a former creative director of Holster Studios.
The creative agency is backed by the7stars as a minority shareholder, while Feiler and Girling own 85 per cent of the company between them.
Feiler, the managing director at Alpha Century, said: "We’re thrilled to be partnering with VictoriaPlumb.com, an extraordinary team with extraordinary plans to shake up their category.
"It was clear from the outset that we’re very much kindred spirits."