Granite Falls STP
Granite Falls, WA · Snohomish County · Publicly Owned Treatment Works
- Average flow
- —
- Design flow
- 1.67 MGD
- NPDES permit
- WA0021130
- Effective
- Permit expires
- July 2025
- Population served
- 3,858
- CWNS 2022
Granite Falls STP is a publicly owned wastewater treatment works in Granite Falls, Snohomish County, Washington, serving about 3,858 residents. Treatment on site includes clarifiers, carrousels / oxidation ditches. It discharges under NPDES permit WA0021130 (effective), which expires in July 2025, with 6 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
- 6
- Effluent violations
- 6
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Granite Falls STP.
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Nearby wastewater treatment plants in Washington
Marysville · 14 mi away
0.17 MGD
Sultan · 17 mi away
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Stanwood · 21 mi away
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Mount Vernon · 25 mi away
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Burlington · 31 mi away
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Sedro-Woolley · 31 mi away
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Mount Vernon · 32 mi away
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Kingston · 32 mi away
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Granite Falls 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 September 11, 2026; facility record last updated November 29, 2025.