NPDES permits in Connecticut
54 permits held by publicly owned wastewater treatment plants · issued by DEEP
Effective
8
Administratively continued
22
Expired
24
Total tracked
54
Connecticut Department of Energy and Environmental Protection (DEEP) runs the NPDES program in Connecticut under delegation from EPA Region 1, issuing and enforcing the discharge permits listed here. Klarifi tracks 54 permits held by publicly owned treatment plants in the state, with status, expiry, design flow and three-year compliance for each. Agency website →
An NPDES permit runs for five years. To keep discharging, a plant must apply for renewal at least 180 days before the expiry date, and the renewed permit usually arrives with tighter effluent limits, new monitoring requirements or a compliance schedule. That is why the year a permit expires is the year a plant starts budgeting for upgrades: nutrient removal, disinfection, capacity or controls.
Permit renewals by year
Largest permit holders in Connecticut
| Facility | City | Avg flow (MGD) | Design (MGD) | NPDES permit | Status | Expires | Violations (3y) |
|---|---|---|---|---|---|---|---|
| Westside Water Pollution Control Facility | Bridgeport | 16.7 | 30 | CT0100056 | Administratively continued | Jun 2024 | 68 |
| Stamford Water Pollution Control Facility | Stamford | 12.5 | 24 | CT0101087 | Expired | Dec 2023 | 8 |
| Norwalk WPCF | East Norwalk | 9.4 | 18 | CT0101249 | Expired | Mar 2026 | 9 |
| Danbury Water Pollution Control Facility | Danbury | 7.8 | 15.5 | CT0100145 | Administratively continued | Jun 2026 | 5 |
| Greenwich WPCF | Greenwich | 5.4 | 12.5 | CT0100234 | Administratively continued | Jul 2024 | 5 |
| Meriden Water Pollution Control Facility | Meriden | 6.49 | 11.6 | CT0100315 | Expired | Dec 2023 | 10 |
| Stratford Water Pollution Control Facility | Stratford | 5.02 | 11.5 | CT0101036 | Expired | Sep 2025 | 36 |
| Eastside Water Pollution Control Facility | Bridgeport | 4.1 | 10 | CT0101010 | Expired | Apr 2026 | 37 |
| Enfield Water Pollution Control Facility | Enfield | 3.01 | 10 | CT0100200 | Administratively continued | Jul 2024 | 0 |
| Piacenti Wastewater Treatment Plant | New London | 4.66 | 10 | CT0100382 | Effective | Apr 2027 | 8 |
| Fairfield Water Pollution Control Facility | Fairfield | 5.9 | 9 | CT0101044 | Effective | Sep 2026 | 5 |
| Hockanum River Water Pollution Control Facility | Manchester | 4.89 | 8.2 | CT0100293 | Effective | Nov 2028 | 12 |
| Killingly Water Pollution Control Fac. | Danielson | 2.95 | 8 | CT0101257 | Administratively continued | Dec 2022 | 1 |
| Milford - Housatonic WPCF | Milford | 4.5 | 8 | CT0101656 | Expired | Oct 2024 | 31 |
| Southington WPCF | Southington (plantsville) | 3.67 | 7.4 | CT0100536 | Expired | Sep 2023 | 3 |
| Torrington Water Pollution Control Facility | Torrington | 2.99 | 7 | CT0100579 | Expired | Oct 2025 | 0 |
| Willimantic WPCF | Willimantic | 1.31 | 5.5 | CT0101001 | Expired | Oct 2023 | 0 |
| Branford Water Pollution Control Facility | Branford | 2.9 | 4.9 | CT0100048 | Expired | Jan 2025 | 0 |
| Montville Water Pollution Control Facility | Montville (uncasville) | 0.75 | 4.5 | CT0100935 | Expired | Oct 2024 | 59 |
| Chesire,water Pollution Control Facility | Cheshire | 1.85 | 4 | CT0100081 | Administratively continued | Sep 2022 | 13 |
| East Hampton Water Pollution Control Facility | East Hampton | 1.04 | 3.9 | CT0024694 | Expired | Sep 2025 | 13 |
| Simsbury Water Pollution Control Facility | Simsbury | 1.58 | 3.8 | CT0100919 | Expired | Feb 2024 | 2 |
| South Windsor Water Pollution Control Facility | South Windsor | 2.01 | 3.75 | CT0100510 | Effective | May 2030 | 5 |
| Glastonbury Water Pollution Control Facility | Glastonbury | 2.17 | 3.64 | CT0100226 | Expired | Apr 2026 | 9 |
| Ansonia Water Pollution Control Facility | Ansonia | 1.3 | 3.5 | CT0100013 | Administratively continued | Nov 2022 | 8 |
All 54 plants in Connecticut →
NPDES permits in Connecticut: 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.