UPDATE: 1 p.m.
Crews responding to a suspected broken 20-inch transmission main on Alapai Street found the source of the water was instead an abandoned 2-inch service pipe.
Board of Water Supply staff have since capped the leaking pipe and reopened Alapai Street between South Beretania and Lusitania streets.
Customers who had earlier been asked to conserve water can resume normal water use, BWS said.
A water main break near the Board of Water Supply this morning has forced the closure of a section of Alapai Street and prompted a water conservation notice for metropolitan Honolulu.
Crews are working to repair the 20-inch transmission main at 1229 Alapai Street and responded to the scene around 8 a.m. today, according to BWS.
Although no customers are without water service at this time, BWS asked customers in the Kalihi to Kaimuki areas (mauka of the H-1 freeway), as well as the upper regions of Nuuanu, Pauoa, Palolo and Manoa valleys to use water sparingly for essential needs only. Cooking, cleaning and personal hygiene would be considered essential.