Whittier Narrows Water Reclamation Plant
301 N. Rosemead Boulevard, South El Monte, CA 91733 · Los Angeles County · Publicly Owned Treatment Works
- Average flow
- 10.72 MGD
- Design flow
- 15 MGD
- NPDES permit
- CA0053716
- Administratively continued
- Permit expires
- July 2026
- Population served
- 297,390
- CWNS 2022
Whittier Narrows Water Reclamation Plant is a publicly owned wastewater treatment works in South El Monte, Los Angeles County, California treating an average of 10.72 million gallons per day against a permitted design capacity of 15 MGD, serving about 297,390 residents. It discharges under NPDES permit CA0053716 (administratively continued), which expires in July 2026, with 14 recorded violations in the last three years.
Treatment technology
Treatment structures and unit processes at Whittier Narrows Water Reclamation Plant.
Treatment structure data not yet analyzed for this facility.
Compliance snapshot (last 3 years)
- Total violations
- 14
- Effluent violations
- 14
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Whittier Narrows Water Reclamation Plant.
No verified contacts on file yet
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Nearby wastewater treatment plants in California
Pico Rivera · 2 mi away
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Los Angeles · 14 mi away
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Pomona · 16 mi away
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Long Beach · 16 mi away
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Burbank · 18 mi away
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Carson · 20 mi away
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Playa Del Rey · 22 mi away
222.56 MGD
Chino · 23 mi away
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Whittier Narrows Water Reclamation Plant: frequently asked 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; facility record last updated May 10, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Activated sludge · Oxidation ditch · all terms