The Marine Corps has issued a “do not use” advisory for the tap water at its Manana Housing Community in Pearl City due to a low chlorine reading on a recent water sample and “visual indications of a potential bacterial issue.”

Officials said the possible bacterial issue has no connection to the recent petroleum contamination in the Navy’s water system, which that serves 93,000 people on Oahu. The Navy’s underground Red Hill fuel storage facility is the apparent source of the contamination.

Capt. Eric Abrams, a spokesman for Marine Corps Base Hawaii, said that the Manana Housing Community has been using Honolulu Board of Water Supply water since Nov. 16, when it transitioned from using the Navy’s water system because of issues with with a booster pump.

The contamination of the Navy’s water supply has extended what was supposed to be a temporary arrangement, with Manana dodging the fuel contamination, which in late November began touching off complaints in other military communities.

Sampling results by the Navy and state Department of Health as well as separate testing in December from the Board of Water Supply detected no petroleum in Manana housing water. But this week, a Manana resident raised concerns about the water’s appearance. The advisory to refrain from using water was issued on Thursday.

In a press release the Marine Corps said: “A close examination of samples taken from a home at Manana revealed an unusual appearance in the water, which might indicate higher levels of bacteria.”

A subsequent testing revealed chlorine levels registering below the required mark. “Out of an abundance of caution, MCBH is now testing to determine if bacteria levels require additional remediation at Manana,” the release stated.

Abrams said Friday that it’s unclear why levels for chlorine, which help prevent bacteria growth, are low.

“We tested the water we’re getting from Board of Water Supply that does not have low chlorine levels,” he said. “So somewhere in the housing community, currently, the chlorine levels are dropping, that’s part of the investigation that we’re doing right now.”

Since the visual appearance and the low chlorine level indicate “there could be a bacterial issue,” Abrams said, “we’re going to do some testing, which will take anywhere from three to five days. And then, once we get that testing back, we will know if there’s something wrong with the water, or not.” In the case of a water problem, he said, “then we can move forward on fixing the issue.”

In the meantime, Abrams said, Marine Corps officials are advising residents to refrain from using the water.