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Notice #: 0001420268-01
Public Notices

Follow Up Samples Test Negative for E. coli Bacteria at Board of Water Supply (BWS) Kahaluu Tunnel

Water is safe to drink. The public was never in any danger.

HONOLULU – Follow up tests at BWS Kahaluu Tunnel were found to be negative for E. coli bacteria.

What should I do?

There is nothing you need to do. Your water continues to be safe to drink. This legal notice is required by Federal and State drinking water regulations.

What Happened?

On June 17, 2023, the Board of Water Supply (BWS) issued a news release notifying the public that a water sample collected before chlorination from BWS Kahaluu Tunnel tested positive on June 15 for the presence of E. coli bacteria. As required by the Ground Water Rule, five (5) additional pre-chlorination samples were immediately collected on June 16, 2023, to follow up on the initial detection. All these five samples collected before chlorination tested negative for E. coli on June 17. As required by Federal and State regulations, BWS is providing this second public notice to report these negative results of the follow up tests. The water from this source is safe to drink because it is routinely disinfected with chlorine before it reaches customers. No further action is required by customers. Water from Kahaluu Tunnel serves the area from Ahuimanu Road to Likelike Highway.

According to the Environmental Protection Agency (EPA), the Ground Water Rule is a regulatory process aimed to reduce the potential risk of illness caused by microbial contamination in ground water. Under the Rule, utilities must test their ground water when coliform is detected in any sample collected from the water system. If E. coli bacteria are found in the ground water source, the Rule requires the public to be notified. While an E. coli detection is not a rule violation, the Rule requires that the public be notified of the findings nevertheless.


On June 15, 2023, BWS detected coliform bacteria from a routine water sample collected on June 13, 2023, from the Kaneohe Police Station. In accordance with the Ground Water Rule, on June 15, 2023, BWS staff collected repeat samples from the Kaneohe Police Station and from all sources before chlorination, that were serving the Kaneohe Police Station, at Kahaluu Tunnel, Waihee Tunnel, and at all pumps from stations at Punaluu Wells II, Waihee Inclined Wells, Kahaluu Well, Kuou Wells II & III, Kaluanui Wells, and Maakua Well. Of all the pre-chlorinated source samples that were collected, only one, Kahaluu Tunnel, was
E. coli positive the following day, on June 16, 2023. The repeat sample from Kaneohe Police Station and samples from all the other well pumps and tunnels were all negative for E. coli bacteria.

With this result and as required by the Rule, on June 16, 2023, the BWS immediately collected an additional five (5) pre-chlorination resamples from Kahaluu Tunnel. After these resamples were collected, Kahaluu Tunnel was shut down as a precaution, because E. coli testing requires at least 18 hours to complete. On June 16, 2023, all five of the additional samples collected before chlorination were found to be negative for E. coli bacteria. As required under the federal Ground Water Rule, BWS is providing this second public notice of these negative findings.

E. coli bacteria can exist in tropical, sub-tropical, and temperate soil and may persist in soil for a number of years. E. coli is a fecal indicator and microbe whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term health effects, such as diarrhea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.

The BWS notified the State Department of Health (DOH) of the follow up test results and is informing the public as required by Federal and State drinking water regulations.

During the time Kahaluu Tunnel was operating, chlorine was being added to disinfect the water before it reaches customers. Water samples collected from the Kaneohe Police Station on June 13 and 15, 2023 had chlorine present and tested negative for E. coli bacteria. Other samples also collected on June 13, 2023, from Heeia Neighborhood Park and on June 15 from Heeia Neighborhood Park, Kaneohe Civic Center Neighborhood Park, and Ben Parker Elementary, also had chlorine present and all tested negative for E. coli bacteria. For this reason, the public was not at risk of E. coli exposure.

What is being done?

The BWS, in consultation with DOH, investigated whether the presence of
E. coli bacteria at Kahaluu Tunnel could be confirmed and found that it could not. All five(5) resamples taken before chlorination at Kahaluu Tunnel were found to be negative for E. coli bacteria. Upon reporting these uniformly negative E. coli results to DOH, BWS received approval from DOH to resume Kahaluu Tunnel operations.

For more information, please contact the BWS Water Quality Division at (808)
748-5841 or the EPA Safe Drinking Water Hotline at 1(800) 426-4791.

Please share this information with all the other people who drink this water, especially those who may not have received this notice directly, for example people in apartments, nursing homes, schools and businesses. You can do this by posting this notice in a public place or distributing copies by hand or mail.
(SA1420268 6/26/23)