California wastewater permits expiring in 2028
24 NPDES permits · 414 MGD combined average flow
24 publicly owned wastewater treatment plants in California hold NPDES permits that expire during 2028, issued by California State Water Resources Control Board. 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 | Violations (3y) |
|---|---|---|---|---|---|
| La City , Pub Works Dept | Van Nuys | 19.79 | CA0056227 | Jan 2028 | 43 |
| Linda County WWTP | Marysville | 3.74 | CA0079651 | Jan 2028 | 22 |
| La City, La-Glendale Water Reclamation | Los Angeles | — | CA0053953 | Jan 2028 | 9 |
| Rodeo Sanitary District | Rodeo | — | CA0037826 | Jan 2028 | 2 |
| Westmorland WWTP | Westmorland | 0.2 | CA0105007 | Mar 2028 | 7 |
| Redway WWTF | Redway | — | CA0022781 | Mar 2028 | 412 |
| Vallejo Flood And Wastewater District | Vallejo | — | CA0037699 | Mar 2028 | 8 |
| Hyperion Treatment Plant | Playa Del Rey | 222.56 | CA0109991 | Apr 2028 | 42 |
| Water Reclamation Plant No. 4 | Thermal | 4.75 | CA0104973 | Apr 2028 | 11 |
| Sewer Authority Mid-Coastside | Half Moon Bay | — | CA0038598 | Apr 2028 | 3 |
| Redding Stillwater Wastewater Treatment Plant | Anderson | 4.24 | CA0082589 | May 2028 | 6 |
| Mt. Shasta WWTP | Mount Shasta | 0.54 | CA0078051 | May 2028 | 37 |
| Copper Cove Wwrf | Copperopolis | 0.46 | CA0084620 | May 2028 | 5 |
| Joint Water Pollution Control Plant | Carson | 154.69 | CA0053813 | Jun 2028 | 19 |
| Seeley County WWTP | Seeley | 0.07 | CA0105023 | Jul 2028 | 266 |
| Mountain House WWTP | Mountain House | 1.42 | CA0084271 | Jul 2028 | 36 |
| Covelo WWTP | Covelo | — | CA0023574 | Jul 2028 | 395 |
| Pinole WWTF | Pinole | — | CA0037796 | Jul 2028 | 2 |
| Eureka Wastewater Treatment Plant | Eureka | — | CA0024449 | Oct 2028 | 21 |
| City Of Red Bluff Wastewater Reclamation Plant | Red Bluff | 1.26 | CA0078891 | Nov 2028 | 31 |
| Burbank Wrp | Burbank | — | CA0055531 | Dec 2028 | 1 |
| Burlingame WWTP | Burlingame | — | CA0037788 | Dec 2028 | 24 |
| Sausalito-Marin City Sanitary District | Sausalito | — | CA0038067 | Dec 2028 | 8 |
| Southern Marin WWTP | Mill Valley | — | CA0037711 | Dec 2028 | 9 |
California permit renewals in 2028: 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 October 26, 2026.
Wastewater terms: NPDES permit · POTW · Biological nutrient removal · Tertiary treatment · Ozonation · Activated sludge · all terms
Cite this page
Journalists, researchers and educators are welcome to quote these figures. Please credit Klarifi as the source and link to this page.
Klarifi. “NPDES permits expiring in 2028: California wastewater plants.” Updated October 26, 2026. https://klarifi.io/facilities/california/permits-expiring/2028Need a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.