Grangeville WWTP
174 Airport Rd, Grangeville, ID 83530 · Idaho County · Publicly Owned Treatment Works
- Average flow
- 0.42 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 0.42 million gallons per day against a permitted design capacity of 0.88 MGD, serving about 3,187 residents. It discharges under NPDES permit ID0020036 (administratively continued), which expires in April 2025, with 3 recorded violations in the last three years. EPA has recorded 1 formal enforcement action naming the plant, the latest in July 2013.
Treatment technology
2 treatment structures and unit processes identified at Grangeville WWTP.
Available with a free Klarifi account
See the full treatment train at Grangeville WWTP: structures, unit processes and planned upgrades, with exact unit counts.
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.
EPA enforcement history
Federal civil enforcement cases, compliance inspections and informal actions recorded for Grangeville WWTP in EPA's ICIS system.
- Formal actions
- 1
- 0 since FY2020
- Compliance actions
- $4M
- required by EPA orders
- EPA inspections
- 0
- none on record
Latest case · Jul 2013
CITY OF GRANGEVILLE - WWTP, IDAHO
Administrative order · CWA, NPDES Permit Violations · Final Order No Penalty · Compliance actions $4M
EPA's description of the case:
“Pursuant to Section 309(a) of the Clean Water Act, EPA Region 10 has issued a compliance order to the City of Grangeville, Idaho (City) for violations of the Citys NPDES permit (Permit No.…”
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Source: EPA ECHO, civil enforcement case 10-2012-0039.
Full case history with a free Klarifi account
Every action against Grangeville WWTP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Key contacts
Decision-makers at Grangeville WWTP.
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Nearby wastewater treatment plants in Idaho
Cottonwood · 13 mi away
0.22 MGD
Kooskia · 15 mi away
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White Bird · 15 mi away
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Kamiah · 21 mi away
0.16 MGD
Nezperce · 22 mi away
0.008 MGD
Craigmont · 26 mi away
0.3 MGD
Weippe · 32 mi away
0.27 MGD
Winchester · 32 mi away
0.01 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 October 26, 2026; facility record last updated May 17, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Activated sludge · Oxidation ditch · all terms