Grand Ronde STP
8630 Grand Ronde Rd, Grand Ronde, OR 97347 · Polk County · Publicly Owned Treatment Works
- Average flow
- 0.16 MGD
- Design flow
- 0.38 MGD
- NPDES permit
- OR0031453
- Effective
- Permit expires
- November 2030
- Population served
- 1,105
- CWNS 2022
Grand Ronde STP is a publicly owned wastewater treatment works in Grand Ronde, Polk County, Oregon treating an average of 0.16 million gallons per day against a permitted design capacity of 0.38 MGD, serving about 1,105 residents. It discharges under NPDES permit OR0031453 (effective), which expires in November 2030, with 1 recorded violation in the last three years.
Treatment technology
2 treatment structures and unit processes identified at Grand Ronde STP.
Available with a free Klarifi account
See the full treatment train at Grand Ronde STP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 1
- Effluent violations
- 1
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Grand Ronde STP.
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Nearby wastewater treatment plants in Oregon
Willamina · 6 mi away
0.48 MGD
Sheridan · 11 mi away
—
Falls City · 16 mi away
0.04 MGD
Hebo · 17 mi away
0.02 MGD
Cloverdale · 17 mi away
0.0092 MGD
Rickreall · 20 mi away
2.77 MGD
Amity · 20 mi away
0.29 MGD
Lincoln City · 22 mi away
2.51 MGD
Grand Ronde STP: 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 November 6, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Equalization tank · Centrate · all terms