Central Johnston County WWTP
Smithfield, NC · Johnston County · Publicly Owned Treatment Works
- Average flow
- 1.5 MGD
- Design flow
- 9.5 MGD
- NPDES permit
- NC0030716
- Administratively continued
- Permit expires
- March 2026
- Population served
- 54,426
- CWNS 2022
Central Johnston County WWTP is a publicly owned wastewater treatment works in Smithfield, Johnston County, North Carolina treating an average of 1.5 million gallons per day against a permitted design capacity of 9.5 MGD, serving about 54,426 residents. Treatment on site includes clarifiers, biogas silos. It discharges under NPDES permit NC0030716 (administratively continued), which expires in March 2026, with 2 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
- 2
- Effluent violations
- 2
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Central Johnston County WWTP.
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Nearby wastewater treatment plants in North Carolina
Clayton · 11 mi away
1.23 MGD
Kenly · 14 mi away
0.25 MGD
Raleigh · 16 mi away
47.06 MGD
Fuquay Varina · 22 mi away
1.44 MGD
Fuquay Varina · 22 mi away
0.07 MGD
Zebulon · 22 mi away
0.92 MGD
Apex · 24 mi away
5.1 MGD
Goldsboro · 24 mi away
5.69 MGD
Central Johnston County 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 24, 2025.