NPDES permits in Hawaii
3 permits held by publicly owned wastewater treatment plants · issued by DOH
Effective
2
Administratively continued
1
Expired
0
Total tracked
3
Hawaii Department of Health (DOH) runs the NPDES program in Hawaii under delegation from EPA Region 9, issuing and enforcing the discharge permits listed here. Klarifi tracks 3 permits held by publicly owned treatment plants in the state, with status, expiry, design flow and three-year compliance for each. Agency website →
An NPDES permit runs for five years. To keep discharging, a plant must apply for renewal at least 180 days before the expiry date, and the renewed permit usually arrives with tighter effluent limits, new monitoring requirements or a compliance schedule. That is why the year a permit expires is the year a plant starts budgeting for upgrades: nutrient removal, disinfection, capacity or controls.
Permit renewals by year
2030: 1 permits
2031: 1 permits
Largest permit holders in Hawaii
| Facility | City | Avg flow (MGD) | Design (MGD) | NPDES permit | Status | Expires | Violations (3y) |
|---|---|---|---|---|---|---|---|
| Hawaii County Hilo WWTP | Hilo | 3.53 | 5 | HI0021377 | Effective | Apr 2030 | 52 |
| Wailua Wastewater Treatment Plant | Kapaa | 0.34 | 1.5 | HI0020257 | Administratively continued | Oct 2024 | 4 |
| County Of Hawaii Papaikou-Paukaa WWTP | Hilo | 0.05 | 0.35 | HI0021113 | Effective | Apr 2031 | 40 |
NPDES permits in Hawaii: questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed September 11, 2026.