Seawater Desalination

Project Update for the Kalaeloa Seawater Desalination Facility

November 2025 – The Honolulu Board of Water Supply and Kalaeloa Desalco LLC are developing an innovative seawater desalination water facility in Campbell Industrial Park that will produce 1.7 to 2.55 million gallons of fresh water daily. Known as the Kalaeloa Seawater Desalination Facility, the plant will be a new source of fresh water to support the needs of Campbell Industrial Park, Kapolei Business Park, and the Deep Draft Harbor. The Project scope is to design, pilot test, permit, construct, start-up, test, and subsequently operate and maintain the Project for a term of twenty years.

The Regulatory and Enhanced Water Quality pilot phase was completed in May 2025. The pilot study proved the proposed reverse osmosis membrane and post-treatment systems can meet the regulatory and enhanced water quality standards established for the project. A reasonable match to the existing water system quality will ensure no detrimental impacts to our customers and their assets.

The pilot study presentation can be viewed at the following link: 

• Regulatory and Enhanced Water Quality Pilot Studies: Kalaeloa Seawater Desalination Facility (10/15/2025) 

The design development period is nearing completion and major permitting is on-going. Construction notice to proceed is anticipated in Spring 2025.

Informational Materials: 

For more details, please see the following or download informational posters  or frequently asked questions .

Location (PDF )

Renderings (PDF )

Process (PDF )

Project Overview (PDF )

Project Partners (PDF )

Project FAQ (PDF )

The Project was authorized by Congress on September 21, 2025, in P.L. 109-70, Section 1638. A U.S. Bureau of Reclamation Grant Application has been accepted for an up to 25% Federal match. A Final EIS was filed in 2008 with OEQC. As part of the grant application, an updated engineering feasibility study financial capability determination, and a NEPA EA FONSI have been completed.

Fresh water demand is approaching BWS Ewa system capacity. BWS is already working to reduce its reliance on groundwater supplies and diversify its supply by encouraging conservation, using recycled water to meet nonpotable water demands, leveraging brackish and saline aquifer supplies where possible. The Ewa District is anticipating a population increase of about 30 percent, or 50,000 people, between 2020 and 2040. Although projected per capita demand is expected to fall from about 168 gallons per capita day (gpcd) in 2020 to about 160 gpcd in 2040, potable demand is anticipated to increase from about 24 mgd in 2019 to nearly 27 mgd in 2030 and additional potable supply will be needed.

Environmental Mitigation:
Saltwater source is from deep wells.  Brine injection into the overlying caprock. JCIP is an underground injection control area regulated by DOH.

Brine will sink because of higher density and flow along the caprock/basal contact along a 4% slope to the ocean and be diluted.  Brine will not impact the benthic nearshore environment.

The desalination process will include an energy recovery system to reduce power consumption and Photovoltaics are planned in a later phase.

Kalaeloa Desalco Project Website

November 2023 – The website for the desalination project being built in Campbell Industrial Park is now available at kalaeloadesalco.com .

Proposed Kalaeloa Seawater Desalination Facility Site

April 2021 – Watch a short video walkthrough of the proposed Kalaeloa Seawater Desalination Facility site.