The Board of Water Supply is asking Leeward Coast residents from Honokai Hale to Makaha to conserve water as it continues to repair a broken 24-inch water main in Makaha.
Repair work is expected to extend through the night.
The water board asks residents to use water sparingly and for priority needs only such as cooking, drinking and personal hygiene.
Residents are urged to refrain from doing laundry, watering lawns and washing cars until repairs are complete.
Motorists should expect delays.
The makai lane of Farrington Highway between Water and Jade streets remains closed.
The mauka lane is being contraflowed for Waianae-bound traffic.
Detour signs and special-duty officers are on scene to alert motorists.