HONOLULU — In consultation with the Hawaii Department of Health, the Board of Water Supply’s investigation into the presence of E. coli bacteria at Kahaluu Tunnel could not be confirmed, according to a BWS news release.

The Environmental Protection Agency’s Ground Water Rule required five additional pre-chlorination re-samples to be collected from Kahaluu Tunnel following the initial finding, which the BWS did on June 16 before shutting down the tunnel as a precaution.

The BWS found all five re-samples were negative for the E. coli bacteria. With these results, BWS received approval from DOH to resume operations at Kahaluu Tunnel.

A routine water sample taken from the Board of Water Supply Kahaluu Tunnel on June 15 contained E. coli bacteria, according to the Board of Water Supply. However, they assure customers that the water remains safe to drink.

What You Need To Know

  • Because water from the Kahaluu Tunnel is routinely disinfected with chlorine before it reaches customers, officials assure customers it is safe to drink

  • Water from this source serves the area from Ahuimanu Road to Likelike Highway

  • Kahaluu Tunnel has been shut down while BWS is investigating the reason for the presence of E. coli

  • The public can contact the BWS Water Quality Division at 808-748-5841 or the EPA Safe Drinking Water Hotline at 1-800-426-4791 for more information

Under federal and state drinking water regulations, the BWS is required to inform the public of any positive finding. Because the water from this source is routinely disinfected before it reaches customers, officials say it is safe to drink. Water from the Kahaluu Tunnel serves the area from Ahuimanu Road to Likelike Highway.

The BWS news release states, “According to the Environmental Protection Agency, the Ground Water Rule is a regulatory process aimed to reduce the potential risk of illness caused by microbial contamination in groundwater.”

BWS explains that the rule requires testing of groundwater when coliform is detected in any sample collected from the water system. If E. coli is detected in the groundwater source, the rule requires the agency to notify the public. Detecting E. coli is not a rule violation, but the rule does require notifying the public. The BWS has also notified the State Department of Health.

According to the BWS, on June 15, the coliform bacteria was detected in a routine water sample collected from the Kaneohe Police Station on June 13. In accordance with the Ground Water Rule, on June 15 BWS staff collected another sample from the Kaneohe Police Station, as well as all sources that serve the police station — Kahaluu Tunnel, Waihee Tunnel, and at all pumps from stations at Punaluu Wells II, Waihee Inclined Wells, Kahaluu Well, Kuou Wells II and III, Kaluanui Wells, and Maakua Well.

Of all the samples collected at these sites, only Kahaluu Tunnel tested positive for E. coli on June 16. The second sample from Kaneohe Police Station and all other well pumps and tunnels were negative for E. coli.

As the Ground Water Rule requires, five additional samples were collected from Kahaluu Tunnel on June 16. BWS then shut the tunnel down. Testing for E. coli requires at least 18 hours.

The presence of E. coli indicates that water may be contaminated with human or animal waste. It can cause short-term negative effects such as diarrhea, headaches or other symptoms. It could pose a special health risk to infants, young children, some elderly and people with severely compromised immune systems. E. coli can exist in tropical, sub-tropical and temperate soil for a few years.

Chlorine was being added to the water before reaching customers while the Kahaluu Tunnel was operating. Samples collected from the Kaneohe Police Station on June 13 and 15 were positive for chlorine and negative for E. coli.

Samples collected from Heeia Neighborhood Park on June 13 and on June 15 from Heeia Neighborhood Park, Kaneohe Civic Center Neighborhood Park and Ben Parker Elementary were also positive for chlorine and negative for E. coli. These results show the public was not at risk of exposure.

After consulting with DOH, BWS is currently investigating the reason for the presence of E. coli. Kahaluu Tunnel will remain closed until BWS concludes its investigation, completes any needed corrective measures, and receives DOH approval to resume normal operation.

The public can contact the BWS Water Quality Division at 808-748-5841 or the EPA Safe Drinking Water Hotline at 1-800-426-4791 for more information.

EDITOR’S NOTE: The article has been updated to note that with the water re-samples testing negative for the E. coli bacteria, BWS has resumed Kahaluu Tunnel operations. (June 19, 2023)

Sarah Yamanaka covers events, environmental and community news for Spectrum News Hawaii. She can be reached at sarah.yamanaka@charter.com.