Traffic was backed up through Nanakuli to Ma'ili Point between 8 and 9 a.m.

Kapolei Police Capt. George Yamamoto said some motorists reported delays of an hour or more.

"Other places have alternative routes but this is a place that's one way in and one way out," Yamamoto said of Farrington Highway. "When something happens, it becomes a choking point."

The break, reported at 10:40 p.m. last night, occurred in a transmission main on Farrington Highway near Ali'inui Drive.

"It's an old main that supplies half the water to the Wai'anae Coast," said Board of Water Supply spokeswoman Denise DeCosta.

Only one of two Honolulu-bound lanes of Farrington Highway was open to traffic this morning because of the repair work, which is expected to take most of the day to complete.

Wai'anae Coast residents had to endure more than slow-moving traffic today. DeCosta said residents have been advised to conserve water because of a drop in the delivery system pressure caused by the break.

Meanwhile, Gov. Linda Lingle today released $1 million for capital improvement projects on Farrington Highway from Nanakuli to Makaha.

The money will be used to install highway median safety barriers from Hakimo Road to Kaukama Road to prevent head-on collisions; for additional lighting from Ala Hema to Makaha Valley Road; and to make sidewalk and crosswalk improvements.