Bursting water
Wai is fresh water and pahū is to burst or explode. The name describes the artesian springs that once rose here — water under pressure from the Koʻolau aquifer, coming up through the plain.
Those springs are why the place was settled and why the sugar mill was put here.
Plantation Village
Waipahu's mill operated from 1897 to 1995. The town preserves Hawaiʻi's Plantation Village, an outdoor museum reconstructing the separate camps that plantation workers lived in — Japanese, Filipino, Portuguese, Chinese, Puerto Rican, Korean — which is as direct an account of how modern Hawaiʻi got its population as exists anywhere.