Who issues NPDES permits in California?

California State Water Resources Control Board issues and enforces NPDES permits for wastewater discharges in California. Klarifi tracks 193 permits held by publicly owned treatment plants in the state.

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

13 permits are administratively continued (the plant applied for renewal and the old permit stays in force) and 79 are recorded as expired, out of 193 permits tracked. 100 are effective.

How many California wastewater permits come up for renewal soon?

20 in 2026, 28 in 2027 and 24 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.

Try for free Log in

NPDES permits in California

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

193 permits held by publicly owned wastewater treatment plants · issued by SWRCB

Effective

100

Administratively continued

Expired

Total tracked

193

California State Water Resources Control Board (SWRCB) runs the NPDES program in California under delegation from EPA Region 9, issuing and enforcing the discharge permits listed here. Klarifi tracks 193 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: 20 permits →2027: 28 permits →2028: 24 permits →

2029: 19 permits

2030: 19 permits

2031: 8 permits

Largest permit holders in California

The 25 largest publicly owned wastewater treatment plants in California 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)
Hyperion Treatment Plant	Playa Del Rey	214	450	CA0109991	Effective	Apr 2028	42
Ccsf- Southeast Water Pollution Control Plant	San Francisco	45.87	400	CA0037664	Expired	Sep 2018	13
Joint Water Pollution Control Plant	Carson	162.85	400	CA0053813	Effective	Jun 2028	19
Orange County Sanitation District Plant 1	Fountain Valley	77.37	332	CA0110604	Administratively continued	Jul 2026	0
Point Loma Wastewater Treatment Plant	San Diego	137	240	CA0107409	Administratively continued	Sep 2022	1689
Sacramento County Wastewater Treatment Plant	Elk Grove	—	181	CA0077682	Expired	May 2026	6
East Bay Mud Main WWTP	Oakland	—	120	CA0037702	Effective	Mar 2031	22
Aliso Creek Ocean Outfall	Dana Point	11.47	104	CA0107417	Effective	Apr 2027	32
San Jose Creek Water Reclamation Plant	Whittier	28.38	100	CA0053911	Effective	Nov 2026	26
Chino	Chino	6.4	85	CA8000409	Effective	Jul 2027	519
La City , Pub Works Dept	Van Nuys	19	80	CA0056227	Effective	Jan 2028	45
Monterey Regional WWTP	Marina	—	75.6	CA0048551	Effective	Feb 2030	5
Regionwide Water Recycling System - Temescal Creek Discharge	Lake Elsinore	—	72	CA8000188	Expired	Sep 2020	34
Santa Rosa Water - Laguna Treatment Plant	Santa Rosa	—	64	CA0022764	Expired	Sep 2025	36
Stockton Rwcf	Stockton	29.2	55	CA0079138	Effective	Jul 2030	57
Central Contra Costa WWTF	Martinez	—	53.8	CA0037648	Effective	Jul 2027	0
Riverside City, Water Quality Control	Riverside	27.72	46	CA0105350	Expired	Oct 2018	2
Lavwma Export And Storage Facilities	Pleasanton	—	41.2	CA0038679	Administratively continued	Jun 2026	76
Colton/san Bernardino Stp, Rix	Colton	21.06	40	CA8000304	Administratively continued	Jul 2018	0
Sunnyvale Water Pollution Control Plant	Sunnyvale	—	40	CA0037621	Expired	Mar 2025	22
Los Coyotes Water Reclamation Plant	Cerritos	—	37.5	CA0054011	Effective	Jan 2027	2
Watsonville WWTF	Watsonville	5.21	36	CA0048216	Expired	Jul 2019	8
City Of San Bernardino WRF	San Bernardino	—	33	CA0105392	Expired	Dec 2022	115
Contra Costa Co San Dist 7a	Antioch	—	31.1	CA0038547	Effective	Mar 2031	1
Terminal Island Treatment Plant	San Pedro	9.8	30	CA0053856	Administratively continued	Jul 2026	17

All 193 plants in California →

NPDES permits in California: 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.

Try Klarifi for free

Create your own trial account and explore how Klarifi can help you.

Try for free