Hawaii County Hilo WWTP
150 Kekuanaoa St, Hilo, HI 96720 · Hawaii County · Publicly Owned Treatment Works
- Average flow
- 3.85 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 3.85 million gallons per day against a permitted design capacity of 5 MGD, serving about 40,979 residents. It discharges under NPDES permit HI0021377 (effective), which expires in April 2030, with 52 recorded violations in the last three years. EPA has recorded 1 formal enforcement action naming the plant, the latest in November 2018.
Treatment technology
2 treatment structures and unit processes identified at Hawaii County Hilo WWTP.
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See the full treatment train at Hawaii County Hilo WWTP: structures, unit processes and planned upgrades, with exact unit counts.
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.
EPA enforcement history
Federal civil enforcement cases, compliance inspections and informal actions recorded for Hawaii County Hilo WWTP in EPA's ICIS system.
- Formal actions
- 1
- 0 since FY2020
- Compliance actions
- $1.3M
- required by EPA orders
- EPA inspections
- 0
- none on record
Latest case · Nov 2018
County of Hawaii Hilo WWTP AO
Administrative order · CWA, NPDES Discharge without a Permit · Final Order No Penalty · Compliance actions $1.3M
EPA's description of the case:
“USEPA issued an Administrative Order for Compliance to the County of Hawaii for violations of its permit under the National Pollutant Discharge Elimination System of the Clean Water Act at the Hilo…”
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Source: EPA ECHO, civil enforcement case 09-2014-1502.
Full case history with a free Klarifi account
Every action against Hawaii County Hilo WWTP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Key contacts
2 verified contacts for Hawaii County Hilo WWTP, with validated emails and direct phone numbers.
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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
0.1 MGD
Kapaa · 322 mi away
0.48 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 October 26, 2026; facility record last updated September 1, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · WWTP · Biosolids · all terms