Holly WWTP
Holly, MI · Oakland County · Publicly Owned Treatment Works
- Average flow
- 0.54 MGD
- Design flow
- —
- NPDES permit
- MI0020184
- Effective
- Permit expires
- October 2026
- Population served
- 8,382
- CWNS 2022
Holly WWTP is a publicly owned wastewater treatment works in Holly, Oakland County, Michigan treating an average of 0.54 million gallons per day, serving about 8,382 residents. Treatment on site includes biogas silos. It discharges under NPDES permit MI0020184 (effective), which expires in October 2026, with 67 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Biogas silos
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Compliance snapshot (last 3 years)
- Total violations
- 67
- Effluent violations
- 1
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
1 verified contact for Holly WWTP, with validated emails and direct phone numbers.
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Names, validated emails and direct phone numbers for decision-makers at Holly WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Michigan
Byron · 13 mi away
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Milford · 15 mi away
0.49 MGD
Wixom · 18 mi away
1.39 MGD
Brighton · 20 mi away
0.34 MGD
Howell · 20 mi away
1.36 MGD
Durand · 20 mi away
0.33 MGD
Walled Lake · 20 mi away
2.13 MGD
Lapeer · 20 mi away
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Holly 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 April 4, 2025.