Louisiana wastewater permits expiring in 2026
18 NPDES permits · 13 MGD combined average flow
18 publicly owned wastewater treatment plants in Louisiana hold NPDES permits that expire during 2026, issued by Louisiana Department of Environmental Quality. The table lists each plant with its permit number, expiry month, average flow, treatment technology and three-year violation count, in order of expiry.
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.
| Facility | City | Avg flow (MGD) | NPDES permit | Expires | Technology | Violations (3y) |
|---|---|---|---|---|---|---|
| Northeast Wastewater Treatment Plant | Bossier City | 3.76 | LA0065978 | Mar 2026 | Clarifiers, Carrousels / oxidation ditches | 0 |
| Sicily Island, Village Of WWTF | Sicily Island | 0.02 | LA0063533 | Mar 2026 | — | 42 |
| Facultative Lagoon | Montgomery | 0.02 | LA0124745 | Mar 2026 | Uncovered lagoons | 183 |
| Village Of Waterproof WWTP | Waterproof | 0.0076 | LA0033031 | Mar 2026 | Uncovered lagoons | 120 |
| Amite City, Town Of- Amite City STP | Amite | 0.26 | LA0038431 | Jun 2026 | Aerated lagoons | 28 |
| Erath, Town Of (wwtp) | Erath | 0.11 | LA0054739 | Jun 2026 | — | 93 |
| Gilbert, Village Of- Sewage District 1 | Gilbert | 0.0041 | LA0049859 | Jul 2026 | — | 56 |
| Village Of Parks WWTF | Parks | 0.92 | LA0050006 | Jul 2026 | — | 114 |
| Colfax Wastewater Treatment Facility | Colfax | 0.21 | LA0033456 | Jul 2026 | Clarifiers, Aerated lagoons, Carrousels / oxidation ditches | 59 |
| Town Of St. Joseph WWTP | Saint Joseph | 0.19 | LA0043621 | Jul 2026 | — | 99 |
| Calcasieu Parish. Sd # 11 WTP | Lake Charles | — | LA0074357 | Jul 2026 | — | 37 |
| Jefferson Parish Department Of Sewerage- Marrero WWTP | Marrero | 6.19 | LA0042048 | Oct 2026 | Clarifiers, Biogas balloons | 5 |
| Vinton, Town Of- Treatment Plant | Vinton | 0.43 | LA0066621 | Oct 2026 | Uncovered lagoons | 66 |
| St Tammany Parish Government-Northlake Behavorial Hospital | Mandeville | 0.04 | LA0127070 | Oct 2026 | — | 29 |
| Village Of Natchez STP | Natchez | 0.0041 | LA0076686 | Oct 2026 | — | 63 |
| Addis Wastewater Treatment Plant | Addis | — | LA0089257 | Oct 2026 | Carrousels / oxidation ditches | 31 |
| St Mary Parish Water & Sewer Commission #4 WWTP | Charenton | 0.04 | LA0100480 | Nov 2026 | — | 0 |
| Simmesport, Town Of (wwtp) | Simmesport | 0.42 | LA0039152 | Dec 2026 | — | 5 |
Louisiana permit renewals in 2026: 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.