A water main break closed 9th Avenue in Palolo between Paalea Street and Kalua Road.
The break in an 8-inch main was reported at 3:10 a.m. Thursday and about 65 homes are without water. A water wagon was being sent to the area.
Repairs are expected to continue through the day.
Motorists are advised to use alternate travel routes in and out of Palolo Valley.