The Navy’s plan to restore safe drinking water to residents in and around Joint Base Pearl Harbor-Hickam, which includes flushing and testing water lines, isn’t expected to be completed until the end of January, according to top Navy officials who briefed state legislators about their plans on Wednesday morning. However, some military families who have been displaced by the water contamination could begin moving home as soon as late next week in what is expected to be a staggered process.

The new timeline is a significant expansion from the Navy’s assessments in early December that it could clean up its water system, which was contaminated with jet fuel in late November, in just a couple of weeks. More than 4,000 military families have moved out of their homes because of the contamination, including about 3,400 who have been living out of hotel rooms, primarily in Waikiki.

In the initial days after the water contamination was confirmed, the Navy began aggressively flushing out hydrants to clear its main distribution lines, spurring the Hawaii Department of Health to issue the Navy a cease and desist order. The Navy didn’t have a permit and there were concerns that the flushing was releasing the contamination into the environment, including storm drains that lead to the ocean and streams. The Navy also asked residents to run their water and flush their toilets to get rid of the contamination, but that prompted reports of overwhelming fuel fumes.

The Navy says it is now working closely with the Hawaii Department of Health and U.S. Environmental Protection Agency on its plans to restore safe drinking water to the approximately 93,000 people who are on its drinking water system. Last month, officials from the agencies signed a Drinking Water Distribution System Recovery Plan, as well as a Drinking Water Sampling Plan.

“The plan includes complete flushing of the entire Navy system, from the source to the faucet, with a comprehensive series of water tests in every neighborhood to certify that drinking water meets safe drinking water standards,” Navy Rear Admiral Blake Converse told lawmakers during a joint briefing before the Senate Committee on Health and the House Committee on Health, Human Services, and Homelessness.

Converse said that its main distribution lines, which carry water to neighborhoods, are being flushed and tested. Navy officials will then be flushing individual homes, schools and businesses. About 10% of homes will be sampled to make sure that the drinking water meets safe standards. The Navy also said that it will test all schools on the Navy’s water system.