Honolulu, Hawaii: water and wastewater capital improvement projects
90 line items · $5.2B · starting 2026–2030 · 1 plan
Honolulu's published capital plans list 90 water, sewer and wastewater line items with a combined planning budget of $5.2B, of which 90 items worth $5.2B sit in the wastewater and sewer departments. The largest single item is Sand Island Wastewater Treatment Plant Secondary Treatment at $2.0B (2025–2031). The ten largest items are listed below; the full list with descriptions and page references is in Klarifi.
A capital improvement plan (CIP) is a city’s multi-year budget for building and replacing infrastructure. The water, sewer and wastewater sections list each project with its budget and the years it is funded, which makes them the earliest public signal that a plant, pump station or pipe network is about to be upgraded, usually two to four years before a contract is awarded.
The largest water and sewer projects in Honolulu
| # | Project | Department | Type | Budget | Years |
|---|---|---|---|---|---|
| 1 | Sand Island Wastewater Treatment Plant Secondary Treatment | Wastewater | Aeration and blowers | $2.0B | 2025–2031 |
| 2 | Honouliuli WWTP Headworks, PS, Energy Savings, Solids Processing and Misc Improvements | Wastewater | Biosolids, sludge and dewatering | $236M | 2025–2029 |
| 3 | Sewer Mainline and Lateral Projects | Sewer | Sewer rehabilitation and I&I | $201M | 2025–2031 |
| 4 | Pearl City/Waipahu Trunk Sewer | Sewer | Force mains and interceptors | $182M | 2025–2030 |
| 5 | Waipahu Wastewater Pump Station Force Main | Sewer | Pump stations | $155M | 2026–2027 |
| 6 | Kailua WWTP - System Improvements | Wastewater | Wastewater treatment plant upgrades | $140M | 2025–2027 |
| 7 | Ewa Beach Wastewater Pump Station Force Main System Improvements | Sewer | Pump stations | $136M | 2025–2028 |
| 8 | Waipahu WWPS Force Mains Rehabilitation | Sewer | Pump stations | $134M | 2025–2031 |
| 9 | Kailua Wastewater Treatment Plant | Wastewater | Wastewater treatment plant upgrades | $111M | 2025–2030 |
| 10 | Wastewater Treatment Plant, Pump Station, and Force Main Projects | Wastewater | Pump stations | $90M | 2025–2031 |
80 more line items in Honolulu, with descriptions and contacts
Klarifi holds every Honolulu line item with its description, the page it appears on and the source document. Track new plans as they are adopted and compare with similar projects in other cities.
Planned spend by start year
Before 2026
$4.5B
57 items
2026
$349M
8 items
2027
$193M
11 items
2028
$107M
4 items
2029
$35M
8 items
2030
$3M
2 items
By department
| Department | Line items | Budget | Share |
|---|---|---|---|
| Wastewater | 31 | $3.1B | 60% |
| Sewer | 59 | $2.1B | 40% |
Project types in Honolulu's plan
Wastewater treatment plants in Honolulu
No publicly owned treatment plant is recorded under Honolulu in the facility directory; the city may be served by a regional plant listed under another municipality. Browse all plants in Hawaii.
Honolulu capital plan questions
Sources and methodology
Budgets and years are as published in Honolulu’s capital improvement plan or adopted budget. Klarifi extracts the water, sewer and wastewater line items from the published document, keeps the page reference for each one, and assigns a project type from the title and description with a keyword classifier. Figures are planning budgets, not awarded contracts, and can change when a plan is re-adopted.
Documents: CIP 2026–2031 (90 line items).
Data refreshed September 11, 2026.