Who issues NPDES permits in Louisiana?

Louisiana Department of Environmental Quality issues and enforces NPDES permits for wastewater discharges in Louisiana. Klarifi tracks 259 permits held by publicly owned treatment plants in the state.

How many NPDES permits in Louisiana are expired or administratively continued?

42 permits are administratively continued (the plant applied for renewal and the old permit stays in force) and 1 are recorded as expired, out of 259 permits tracked. 216 are effective.

How many Louisiana wastewater permits come up for renewal soon?

18 in 2026, 25 in 2027 and 70 in 2028. Each year has its own renewal calendar with the plants listed.

How do I look up an NPDES permit number?

Enter the permit number (two letters and seven characters, for example TX0021873) or the plant name in the lookup on the NPDES page; each result opens the plant profile with status, expiry, design flow and the three-year violation count.

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NPDES permits in Louisiana

Name: NPDES permits held by wastewater treatment plants in Louisiana
Creator: Klarifi
License: https://klarifi.io/terms-of-service

259 permits held by publicly owned wastewater treatment plants · issued by LDEQ

Effective

216

Administratively continued

Expired

Total tracked

259

Louisiana Department of Environmental Quality (LDEQ) runs the NPDES program in Louisiana under delegation from EPA Region 6, issuing and enforcing the discharge permits listed here. Klarifi tracks 259 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

2026: 18 permits →2027: 25 permits →2028: 70 permits →

2029: 34 permits

2030: 50 permits

2031: 30 permits

Largest permit holders in Louisiana

The 25 largest publicly owned wastewater treatment plants in Louisiana by permitted design flow, with NPDES permit number, status and expiry. Source: EPA ICIS-NPDES via Klarifi.
Facility	City	Avg flow (MGD)	Design (MGD)	NPDES permit	Status	Expires	Violations (3y)
Bernice, Town Of	Bernice	0.11	603	LA0034568	Effective	Aug 2031	12
Baton Rouge, City Of	Scotlandville	11	54	LA0036439	Effective	Jul 2029	30
South Wastewater Treatment Plant	Baton Rouge	33	54	LA0036412	Effective	Jun 2029	20
Jefferson Parish Department Of Sewerage- East Bank WWTP	Elmwood	20.66	33	LA0066630	Effective	Jul 2028	0
Red River Wastewater Treatment Plant	Bossier City	4.48	12	LA0053716	Effective	May 2028	0
Wards 5 & 8 Joint Sewerage Commision	Patterson	2.55	12	LA0068381	Effective	Sep 2030	99
St. Bernard Parish - Munster WWTP	Chalmette	3.77	11	LA0040177	Administratively continued	Oct 2025	2
Sewerage & Water Board Of New Orleans Westb Ank Sewage	New Orleans	10.13	10	LA0038105	Effective	Nov 2029	1
Jefferson Parish Department Of Sewerage- Marrero WWTP	Marrero	6.19	9.6	LA0042048	Effective	Oct 2026	5
Wastewater Treatment Plant	Pineville	—	9	LA0033464	Effective	Dec 2030	52
Thibodaux, City Of- Wastewater Treatment Facility	Thibodaux	2.1	8	LA0032948	Effective	Jul 2029	77
Bridge City Wastewater Treatment Plant	Bridge City	1.59	7.23	LA0042064	Effective	Feb 2031	14
Monroe, City Of (wpc Cntr)	Monroe	6.09	—	LAL038741	Effective	Dec 2030	78
Lafayette Consolidated Government - Ambassador Caffery STP	Lafayette	4.38	6	LA0042561	Administratively continued	Oct 2024	0
Northeast Wastewater Treatment Plant	Bossier City	3.76	6	LA0065978	Administratively continued	Mar 2026	0
Plaquemines Parish Government- Belle Chasse WWTP	Belle Chasse	1.34	6	LA0044032	Effective	Jun 2030	14
Slidell, City Of	Slidell	2.95	6	LA0047180	Effective	Sep 2030	3
Plant B	Lake Charles	5.74	—	LAL036366	Effective	Dec 2030	73
Gretna City Of Wastewater Treatment Plant	Gretna	1.17	5	LA0041262	Effective	Aug 2028	10
Vinton, Town Of- Treatment Plant	Vinton	0.43	4.6	LA0066621	Effective	Oct 2026	66
Ruston, City Of- Northside Wastewater Treatment Plant	Ruston	3.22	4	LA0036323	Effective	Jun 2028	81
Crowley WWTP	Crowley	1.1	3.5	LA0041254	Effective	Oct 2030	43
Carrollton Water Purification Plant	New Orleans	3.38	—	LA0000086	Administratively continued	Jun 2025	53
St. Charles Parish Council--Destrehan WWTP	Destrehan	2.27	3.2	LA0073539	Effective	May 2027	0
Deridder City Of - Deridder Animal Shelter	Deridder	0.7	3.03	LA0038407	Effective	Jan 2031	40

All 259 plants in Louisiana →

NPDES permits in Louisiana: 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.

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