General Electric Co. predicts that water purification could grow from a drop in the corporate bucket to a major growth driver within years, just as its wind unit did.

The largest US conglomerate has taken about a decade to build its water unit, which focuses on large-scale treatment and purification for municipal and industrial water users, through five takeovers costing about €2.8 billion.

With an estimated €1.7 billion in revenue, the water business remains a sliver of the €110 billion in sales the world's largest maker of jet engines and electricity-producing turbines is expected to generate this year.

The unit's small size has lead some investors to wonder if GE might prefer to sell it to focus on businesses where it can better enjoy the benefits of scale.

But executives with Fairfield, Connecticut-based GE said water has the potential to become a major profit contributor.

"What GE tries to do is to align the company with some of the mega-trends, the mega-challenges of the world. Energy is one, healthcare is the other, and the third one is water," said Heiner Markhoff, president and chief executive officer of GE Water & Process Technologies.

While arid areas of the world, from the Middle East to the southwestern US, have long coped with water shortages, rapid population growth and rising environmental regulations are making water scarcity and purification a more prominent issue in temperate, wetter areas.

GE is not the only major multinational to see potential in water. Its rivals include German conglomerate Siemens AG and No. 2 US chemical company Dow Chemical Co., as well as smaller companies including Danaher Corp. and Nalco Holding Co.

GE and its rivals are focusing on scarcity, and the growing competition for water among residential and commercial users.