NOTICE OF CLEAN WATER BRANCH RECOMMENDATIONS FOR
WATER POLLUTION CONTROL PERMIT FOR
THE CITY AND COUNTY OF HONOLULU
BOARD OF WATER SUPPLY
HALEIWA WELLS GRANULAR ACTIVATED CARBON WATER TREATMENT FACILITY
NPDES PERMIT NO. HI 0021950
DOCKET NO. HI 0021950
PUBLIC COMMENT PERIOD
February 11, 2026 – March 13, 2026
The Hawaii Department of Health (DOH), Clean Water Branch (CWB) tentatively recommends to the Director of Health (Director) to issue a National Pollutant Discharge Elimination System (NPDES) Permit to regulate and impose water pollution control requirements on the discharge standby contactor refreshing water associated with the maintenance of the Granular Activated Carbon (GAC) beds; dewatering and disinfection water associated with the removal of spent GAC; defining, backwashing/stratification, and forward flushing water associated with the preparation of new GAC beds; water from routine backwashing of the GAC beds; and well certification discharges to receiving State waters, subject to special conditions, to:
CITY AND COUNTY OF HONOLULU
BOARD OF WATER SUPPLY (HBWS)
A permit for such discharge would expire five (5) years from the effective date of the permit. The HBWS (Permittee) owns and operates the Facility, located at: 66-333 Kamehameha Highway, Haleiwa, Hawaii 96712.
The Facility treats groundwater using four (4) GAC contactors. The GAC is the consumable component of the water treatment facility used to remove the target contaminants from the groundwater supplies used for potable water. The contactors can produce approximately two (2) million gallons per day of potable water. The contactors are operated as a pair in series with either contactor in the lead position. They also can be operated in a single contactor configuration with the other contactor as a standby.
HBWS requests to discharge wastewater associated with routine operation and maintenance of the GAC contractors. Discharges will be generated from removing spent GAC, preparing new GAC beds, backwashing GAC beds, refreshing standby contactors, and well certification to Opaeula Stream at Outfall Serial No. 001 at coordinates: Latitude 21°34’50” N, and Longitude 158°6’4″ W.
The receiving water, Opaeula Stream, is classified by the DOH as Class 2 Inland Waters under Hawaii Administrative Rules (HAR), Sections 11-54-5. It is the objective of Class 2 waters to protect their use for recreational purposes, the support and propagation of aquatic life, agricultural and industrial water supplies, shipping, and navigation. The uses to be protected in this class of waters are all uses compatible with the protection and propagation of fish, shellfish, and wildlife, and with recreation in and on these waters. Class 2 waters shall not act as receiving waters for any discharge which has not received the best degree of treatment or control compatible with the criteria established for these classes.
Persons wishing to comment upon or object to the proposed NPDES Permit or to request a Public Hearing, should submit their comments or requests in writing no later than 30 calendar days after the date of this notice, either through E-mail at cleanwaterbranch@doh.hawaii.gov or by mail at P.O. BOX 3378, Honolulu, Hawaii 96801-3378.
Copies of the Public Notice Permit recommended by CWB and other information are available for public inspection, Monday through Friday (excluding holidays) from 7:45 a.m. until 4:15 p.m., at the DOH Clean Water Branch office located at 2827 Waimano Home Road, Room 225, Pearl City, Hawaii 96782. Copies may be bought. Electronic copies of the proposed Public Notice Permit and other information are also available online at https://health.hawaii.gov/cwb/clean-water-branch-home-page/public-notices-and-updates/.
For more information or if you have special needs due to a disability and require aid in inspecting and/or commenting on the Public Notice Permit and related information, please contact Mr. Reef Migita, Supervisor of the Engineering Section, Clean Water Branch, at the above address or (808) 586-4309 (Voice) as soon as possible before the end of the comment period. For those who use a TTY/TDD, please call through Sprint Relay Hawaii, at 1 711 or 1-877-447-5991. If a request for assistance is made after the end of the comment period, the CWB will try to fulfill the request. However, fulfillment prior to a final determination cannot be guaranteed. Requests submitted as early as possible are more likely to be fulfilled.
All written comments and requests received on time will be considered. If the Director determines that there is significant public interest, a Public Hearing may be held after at least 30 calendar days of Public Notice.
If CWB believes, after considering all timely written comments at any Public Hearing that may be held, that no substantive changes to the conditions of the Public Notice Permit are necessary or warranted, then CWB may recommend to the Director that the NPDES Permit be issued.
Please notify anyone you know who would be interested in this matter.
DARRYL LUM, P.E.
Clean Water Branch Chief
(SA1519573 2/11/26)
