The Navy has completed flushing system waterlines at the Pearl City Peninsula military housing neighborhood as it tries to clear out fuel contamination of its water system that serves 93,000 people on Oahu.

The contamination is believed to have come from the Navy’s Red Hill Bulk Fuel Storage Facility.

A Friday news release from the Interagency Drinking Water System Team, which includes the Navy, Army, Hawaii Department of Health and U.S. Environmental Protection Agency, said the system flushing in that area, which began Monday, wrapped up Wednesday and that water samples were sent to a mainland lab for testing, with results expected back next week.

Pending the results, workers will move onto flushing individual Pearl City Peninsula homes, the release said.

Pearl City Peninsula was flushed first, the release said, because of its proximity to the Waiawa well, which has been the source of the Navy’s drinking water since the Red Hill and Halawa wells were closed Nov. 28 and Dec. 3, respectively.

The Navy said it is flushing its water distribution systems in accordance with the Drinking Water Distribution System Recovery Plan signed Dec. 17 by the Navy, Army, DOH and EPA.

Working with contractors, the Navy is connecting granular activated carbon filtration units to fire hydrants, with the filtered water discharged into storm drains or over land with DOH and EPA oversight, the release said. “The purpose of filtering through GACs is to ensure the water being discharged to the storm drains or land applications is free from petroleum products that may threaten human health and the environment.”

The Navy earlier in the Red Hill water crisis had started flushing out hydrants, but on Dec. 11 DOH issued a cease-and-desist order, saying the Navy wasn’t following state guidance.

In response, the Navy ordered emergency shipments of the GAC filtration systems.

“Once zones are flushed, water samples are taken and sent to a certified lab on the mainland for testing to confirm the drinking water meets federal and state standards,” the release said. “Flushing will continue until testing confirms the drinking water is fit for consumption as determined by Hawai‘i DOH.”

Waterline flushing is ongoing in the Aliamanu Military Reservation, Joint Base Pearl Harbor-Hickam and Red Hill housing areas.

A regularly updated flushing progress map can be found at navy.mil/jointbase water.