Grangeville WWTP
Grangeville, ID · Idaho County · Publicly Owned Treatment Works
- Average flow
- 0.39 MGD
- Design flow
- 0.88 MGD
- NPDES permit
- ID0020036
- Administratively continued
- Permit expires
- April 2025
- Population served
- 3,187
- CWNS 2022
Grangeville WWTP is a publicly owned wastewater treatment works in Grangeville, Idaho County, Idaho treating an average of 0.39 million gallons per day against a permitted design capacity of 0.88 MGD, serving about 3,187 residents. Treatment on site includes clarifiers, carrousels / oxidation ditches. It discharges under NPDES permit ID0020036 (administratively continued), which expires in April 2025, with 3 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
- 3
- Effluent violations
- 3
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Grangeville WWTP.
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Nearby wastewater treatment plants in Idaho
Cottonwood · 13 mi away
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Kooskia · 15 mi away
0.11 MGD
White Bird · 15 mi away
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Kamiah · 21 mi away
0.12 MGD
Nezperce · 22 mi away
—
Craigmont · 26 mi away
—
Weippe · 32 mi away
—
Winchester · 32 mi away
0.03 MGD
Grangeville 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 May 17, 2025.