City officials warned Leeward Oahu commuters to expect long delays as repairs on a broken water main on Farrington Highway in Nanakuli continue through tonight.

The 24-inch water main broke Thursday night near Pohakunui Avenue. The water main supplies 60 percent of the water to the Leeward Coast, and Board of Water Supply officials asking all residents from Honokai Hale to Makaha to conserve water. “This means using water for essential needs only, such as cooking, drinking, and personal hygiene,” city officials said in a news release.

The repairs have closed all east-bound lanes of Farrington Highway between Pohakunui Avenue and Kahe Power Plant. The west-bound lanes are being contra-flowed and HPD officers are at the site to assist with directing traffic.

As the afternoon rush hour intensifies, traffic officials plan to use both available lanes to let Waianae-bound traffic pass only. They will intermittently open one of those lanes to town-bound traffic, according to HPD Assistant Chief Clyde Ho.

More than 45,000 residents live on the Leeward Coast and the area sees about 43,000 vehicle trips a day, officials say. Acting Department of Transportation Services Director Jon Nouchi encouraged residents to wait until after peak traffic hours to return home if they can.

Officials said customers in Nanakuli are experiencing either low water pressure or no water service.

“Motorists are advised to expect traffic delays and to plan their commute accordingly as work to repair the water main and roadway will continue overnight into the weekend,” officials said this afternoon.

Officials say they hope to have the 20-foot main crack repaired Saturday and the road fixed Sunday, but they added that it’s hard to say “definitively” how long the repairs will take.

Ka Waihona o Ka Na’auao Public Charter School were closed today. Nouchi added that city transportation officials requested their federal counterparts to open the Kolekole Pass as an alternate route, but they were told that wasn’t possible.