Waipahu is a former sugar plantation town and now census-designated place (CDP) located in the ʻEwa District on the island of Oʻahu in the City & County of Honolulu, Hawaiʻi. As of the 2000 Census, the CDP population was 33,108. The U.S. postal code for Waipahu is 96797.
Waipahu is a name of an artesian spring. In Hawaiian, Waipahu is derived from wai, meaning water, and pahū, meaning "burst or gush forth". The early Native Hawaiians took pleasure in the cool and clear water gushing from the ground and named this spring Waipahu. Before the Western civilization set foot in Hawaii, the Hawaiians considered Waipahu to be the capital of Oahu. Royalty in the Kingdom of Hawaii would often gather and enjoy the fresh water from the spring Waipahu.
In 1897, Oahu Sugar Company was incorporated and its Board of Directors located the sugar mill in Waipahu. The Company's managers from 1897 to 1940 were: August Ahrens (1897–1904); E.K. Bull (1904–1919); J.B. Thomson (1919–1923); E.W. Greene (1923–1937); and Hans L'Orange (1937–1956). Oahu Sugar Company shut down plantation operations after the 1995 harvest.