The state Health Department is warning the public about elevated bacteria levels at popular Kaimana Beach in Waikiki.
Officials said tests conducted Wednesday showed levels of enterococci in the area exceeded water quality standards by nearly three times.
Warning signs have been posted, and beachgoers are being urged to stay out of the water.
"Contact with water in this area may cause illness," the Health Department said.
Kaimana is also known as Sans Souci, and is popular with most visitors and residents.
Myron Honda, of the Clean Water Branch, said new samples were taken Thursday and those resulted will be in Friday.
Officials don't know what's causing the higher bacteria levels, and Honda acknowledged the finding was unusual.
Since 2014, the Health Department has taken 166 water quality samples at Kaimana, and this is only the second time that enterococci levels came back above the threshold. The first was in 2015.
Honda also said that while the higher bacteria levels are concerning, they are not as high as they would be if there were a sewage spill in the area.
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