Health Department warns of high bacteria levels at Kailua Bay

The Hawaii Department of Health is advising the public to avoid waters near the city’s regional wastewater treatment plant outfall — which includes the popular Kailua Bay — due to continuous, elevated levels of enterococcus bacteria.

Since April 8, the Health Department said, the city has documented wastewater discharges at the Kailua Regional Wastewater Treatment Plant that exceed bacteria limits in its state permit.

Under this permit, the City and County of Honolulu is allowed to discharge treated effluent through a deep ocean outfall about 5,000 feet from the shoreline, at a depth of 105 feet below the surface of the water. But the city must monitor levels of enterococcus via a “single grab sample” taken at a specified point within the treatment plant — after treatment but prior to discharge.

The samples have exceeded elevated levels of enterococcus on 13 days total, according to the Health Department as early as April 8 and as recent as Thursday. The highest exceedances, DOH said, were reported on April 28 and May 1, and were over six times the limit.

Accordingly, the Health Department has issued a water quality advisory for these exceedances, advising the public to remain out of the water near this wastewater treatment plant and nearshore area along Kailua Beach.

The city this week said samples collected on April 27, 28, 29, 30, and on May 1, 2, 3, and 4 displayed elevated levels of enterococcus. A single sample taken April 26 was within normal ranges.

The city said it would continue to collect additional daily samples of the effluent, as well as daily samples at shoreline stations, and that signs are posted to stay out of waters around the outfall.

DOH said it will continue to oversee the city’s response to the ongoing discharge violations, and directed the city to post the warning signs.

These warning signs will remain up, DOH said, until it is confident “that coastal waters have returned to normal and the City returns to compliance with effluent discharge limitations.” The public is advised to stay out of the affected waters until warning signs have been removed.

Enterococcus is a bacterium used as an indicator of waterborne pathogens, according to the Health Department. The city said it is naturally present in Oahu’s soils and enters the ocean via storm runoff.