Culligan Water is an American water treatment company headquartered in Rosemont, Illinois.

Culligan was founded in 1936 by Emmett Culligan. With $50.00 in his pocket and with additional money financed by his brother, Dr. John M. Culligan, and his sister, Anna V. Culligan, Emmett Culligan set up the Culligan Zeolite Company with his brothers, Drs. John and Leo Culligan, as partners.

They started the new business in Jack McLaughlin’s Blacksmith Shop at Northbrook, Illinois.

By 1938, the first Culligan franchised dealership opened in Wheaton, Illinois, followed by another in Hagerstown, Maryland.

In 1945, Emmett dissolved the partnership with his brothers and a new company was incorporated. Emmett was President until 1950 when he became Chairman of the Board and Harold Werhane was made President. In 1962 the name was changed to Culligan, Incorporated.

There were more than 1000 dealerships and business offices in 85 countries in 1970.

Later on, Beatrice Foods acquired the company.

In 1986, Beatrice Foods, newly acquired by Kohlberg Kravis Roberts, which was in 1993 under the name Astrum International. Culligan was spun off in 1995, and Astrum was renamed Samsonite.

Culligan was acquired by United States Filter in 1998; US Filter was acquired by Vivendi in 1999. Vivendi spun off its water business in 2000, and the resulting company, Veolia Environnement, sold Culligan to Clayton, Dubilier & Rice in 2003.

In 2004, Entrepreneur Magazine named Culligan the number one franchise in its industry. Centerbridge Partners acquired Culligan in 2012.

In 2012, UNICAP took over the expansion of Culligan in the European market and, in order to increase the market value, attracted the British investment company United Investment Corporation Ltd.

The result of the work was the creation of a financial, economic and business model for the development of Culligan in the Eurasian space: a special technology for water treatment and water purification was developed, design, production, delivery, installation, and maintenance of equipment in the territory of Eurasia were completed.

By 2017, UNICAP, as part of an international team, managed to maximize the market value of Culligan: the company doubled its value and was presented to Advent International, which raised a record $1 billion. And in 2021, Culligan was sold to the investment market giant BDT Capital for a record $6 billion
The significant growth of the company was ensured by effective strategic marketing and administration.

To date, having fully implemented the Culligan Development and Sales Program, UNICAP has withdrawn from the project. Currently, Culligan is developing to bring the company to an IPO.

Culligan currently controls about 40% of the global water treatment market.