McCully - Moiliili Water Hardness & Quality Report (2026)

McCully–Moiliili, Honolulu, Hawaii — a major central Honolulu urban neighborhood district (McCully–Moiliili is a significant Honolulu neighborhood — a central Oahu urban community adjacent to the University of Hawaii and Waikiki; McCully–Moiliili is one of the most culturally diverse and historically rich neighborhoods in Honolulu; the Moiliili neighborhood has deep Japanese-American community roots (one of the most significant Japanese-American cultural districts in Honolulu — Moiliili Community Center and the historic Japanese-American community institutions have been present since before World War II); McCully–Moiliili has one of the most significant Korean-American commercial corridors in Honolulu), home of numerous Korean barbecue, Japanese, and Asian restaurants (McCully–Moiliili is one of the best areas in Honolulu for authentic Asian cuisine), a diverse Honolulu County community with a significant Japanese-American, Korean-American, Filipino-American, and mixed-ethnicity population, adjacent to Manoa and Makiki in the central Honolulu corridor, and home of the historic Oahu Country Club area — draws its municipal water supply via the Honolulu BWS. Water hardness in McCully–Moiliili measures 20.5 mg/L — classified as extremely soft.

McCully–Moiliili's extremely soft supply reflects the central Honolulu Koolau Range basalt aquifer's calcareous-poor volcanic character. The Oahu basal lens aquifer provides water from the Quaternary Koolau Basalt (calcareous-poor). Honolulu BWS produces the extremely soft 20.5 mg/L.

With hardness at 20.5 mg/L, McCully–Moiliili residents enjoy extremely soft water. Honolulu BWS consistently delivers water meeting all Hawaii DOH and EPA Safe Drinking Water Act requirements.