Zillah Wastewater Treatment Plant
Zillah, WA · Yakima County · Publicly Owned Treatment Works
- Average flow
- —
- Design flow
- 1.47 MGD
- NPDES permit
- WA0020168
- Effective
- Permit expires
- October 2030
- Population served
- 3,434
- CWNS 2022
Zillah Wastewater Treatment Plant is a publicly owned wastewater treatment works in Zillah, Yakima County, Washington, serving about 3,434 residents. Treatment on site includes clarifiers, carrousels / oxidation ditches. It discharges under NPDES permit WA0020168 (effective), which expires in October 2030, with 0 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
- 0
- Effluent violations
- 0
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Zillah Wastewater Treatment Plant.
No verified contacts on file yet
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Nearby wastewater treatment plants in Washington
Toppenish · 2 mi away
0.67 MGD
Zillah · 3 mi away
—
Toppenish · 4 mi away
0.06 MGD
Granger · 5 mi away
—
Sunnyside · 13 mi away
1.31 MGD
Sunnyside · 14 mi away
1.17 MGD
Harrah · 14 mi away
0.03 MGD
Yakima · 16 mi away
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Zillah Wastewater Treatment Plant: 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 29, 2025.