Hermiston WWTP
2205 N 1st Pl, Hermiston, OR 97838 · Umatilla County · Publicly Owned Treatment Works
- Average flow
- 1.48 MGD
- Design flow
- 2.94 MGD
- NPDES permit
- OR0020761
- Effective
- Permit expires
- January 2028
- Population served
- 18,775
- CWNS 2022
Hermiston WWTP is a publicly owned wastewater treatment works in Hermiston, Umatilla County, Oregon treating an average of 1.48 million gallons per day against a permitted design capacity of 2.94 MGD, serving about 18,775 residents. It discharges under NPDES permit OR0020761 (effective), which expires in January 2028, with 0 recorded violations in the last three years. EPA has recorded 1 formal enforcement action naming the plant, the latest in May 2008.
Treatment technology
3 treatment structures and unit processes identified at Hermiston WWTP.
Available with a free Klarifi account
See the full treatment train at Hermiston WWTP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 0
- Effluent violations
- 0
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 Hermiston WWTP in EPA's ICIS system.
- Formal actions
- 1
- 0 since FY2020
- Penalties assessed
- $1,810
- all cases
- Compliance actions
- $10,000
- required by EPA orders
- EPA inspections
- 2
- latest Mar 2014
Latest case · May 2008
CITY OF HERMISTON WASTE WATER TREATMENT FACILITIES
Administrative order · CAA, Prevention of Accidental Release/Risk Management Plans (RMPs) · Final Order With Penalty · Penalty $1,810 · Compliance actions $10,000
Source: EPA ECHO, civil enforcement case 10-2008-0079.
Full case history with a free Klarifi account
Every action against Hermiston WWTP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Key contacts
1 verified contact for Hermiston WWTP, with validated emails and direct phone numbers.
Unlock 1 verified contact
Names, validated emails and direct phone numbers for decision-makers at Hermiston WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Oregon
Umatilla · 4 mi away
0.67 MGD
Stanfield · 7 mi away
—
Heppner · 36 mi away
0.13 MGD
Athena · 39 mi away
0.2 MGD
Arlington · 44 mi away
0.06 MGD
Elgin · 71 mi away
0.2 MGD
Biggs · 74 mi away
0.03 MGD
Long Creek · 79 mi away
0.03 MGD
Hermiston 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 April 6, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Anaerobic digester · Lift station · all terms