State publishes final EIS for new Central Maui wastewater facility in Waikapū

The state Office of Planning and Sustainable Development has published a final environmental impact statement for a new 14.9-acre Central Maui Wastewater Reclamation Facility on former agricultural lands in Waikapū located between Honoapiʻilani and Kūihelani highways.

The department will also install portions of a sewage pipeline and a recycled water pipeline to connect the site with the future 1,400-unit Waikapū Country Town development. Crews will build a new facility access road to complete the project.

The Waikapū Country Town development will purchase the facility’s R-1 water and use it for irrigation of landscaping, parks, school yards and agricultural fields. Other service areas include Wailuku and Waikapū, along with state projects in Pūlehunui.

Project documents for the county’s wastewater plant report that local irrigation demand would use essentially all the recycled water the new plant generates.

Department of Environmental Management also proposes developing an onsite soil aquifer treatment system

The project design requires several related offsite infrastructure improvements. Project plans include a wastewater pump station near the existing master-planned Kehalani community and a sewage pipeline running from the station to the new reclamation facility.

Planners expect the new Waikapū wastewater plant to recycle nearly all its highly treated water for local irrigation across more than 1,200 acres in Central Maui.

The Central Maui facility will produce R-1 recycled water, which the state Department of Health approves for irrigating food crops and landscaping.

In another indication that the project is graining traction, the Maui County Council’s Budget, Finance and Economic Development Committee will consider a $3.5 million funding bill for the Waikapū wastewater facility at its meeting beginning at 9 a.m. today (March 3) in Council Chambers.

Bill 30 transfers $3.5 million in general fund savings to the Central Maui Regional Wastewater Reclamation Facility.

On Jan. 26, Mayor Richard Bissen asked state lawmakers for $10.5 million to support the Central Maui facility. Bissen said the planned facility is essential for supporting housing development, growth and wastewater capacity in Central Maui.

When asked about the project timeline, Department of Environmental Management Director Shayne Agawa said the county plans to open project bids in mid 2027. Then, after about two years of construction, the wastewater treatment plant should be operational in either 2029 or early 2030, he said.

The “planning-level cost” for construction is approximately $130.6 million dollars in 2025 dollars. This cost estimate includes the pipelines under the future Waiʻale Road extension.