Hawaii County Hilo WWTP
Hilo, HI · Hawaii County · Publicly Owned Treatment Works
- Average flow
- 3.53 MGD
- Design flow
- 5 MGD
- NPDES permit
- HI0021377
- Effective
- Permit expires
- April 2030
- Population served
- 40,979
- CWNS 2022
Hawaii County Hilo WWTP is a publicly owned wastewater treatment works in Hilo, Hawaii County, Hawaii treating an average of 3.53 million gallons per day against a permitted design capacity of 5 MGD, serving about 40,979 residents. Treatment on site includes clarifiers, biogas silos. It discharges under NPDES permit HI0021377 (effective), which expires in April 2030, with 52 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Compliance snapshot (last 3 years)
- Total violations
- 52
- Effluent violations
- 2
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
2 verified contacts for Hawaii County Hilo WWTP, with validated emails and direct phone numbers.
Unlock 2 verified contacts
Names, validated emails and direct phone numbers for decision-makers at Hawaii County Hilo WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Hawaii
Hilo · 7 mi away
0.05 MGD
Kapaa · 322 mi away
0.34 MGD
Hawaii County Hilo WWTP: frequently asked 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; facility record last updated September 1, 2025.