California Stormwater Intelligence

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Waterbody profile

Official Water Board record · 2026 cycle

Castaic Lake

Waterbody ID (WBID): CAL4035100020091208105546
County / counties: Los Angeles
Regional Water Board: Regional Board 4 - Los Angeles Region
Waterbody type: Lake & Reservoir
Condition category: Category 5 — 303(d) listed, TMDL required
Integrated Report cycle: 2026

303(d) listings (2)

Each row is one official listing decision from Appendix A of the Final 2026 California Integrated Report. Source terminology is preserved as published.

Pollutant / stressor	Decision ID	Final listing decision	Decision status	TMDL requirement status	TMDL project	TMDL priority
MercuryMetals	149500	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
PCBs (Polychlorinated biphenyls)Toxic Organics	84621	List on 303(d) list (TMDL required list)	Original	5A — TMDL still required	—	Low

Source & provenance

Agency: California State Water Resources Control Board
Report: Final 2026 California Integrated Report
Dataset: Appendix A — 2026 303(d) List of Impaired Waters
Imported: Sep 16, 2026, 10:56 PM UTC
Waterbody ID: CAL4035100020091208105546
CALWNUM: 4403.51
WBD code: 180701020304, 180701020305, 180701020306
Geometry: Official Water Board GIS (CA_WATERBOARDS_GIS_FINAL_2026)

View official Water Board fact sheet ↗Download Appendix A source file ↗

Location

Official 2026 Water Board geometry. Demonstration facility markers are shown for context only.

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Watershed: —
Assessed size: 2231.41 Acres

Derived facility associations

Industrial stormwater facilities geographically associated with this waterbody. These are derived spatial associations, not Water Board findings.

Derived

Amazon com Services LLC DPS5

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

ASC Process Systems

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Bay Center Foods LLC

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Bloomers Metal Stamping Inc

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Canyon Plastics Inc

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Canyon Plastics LLC

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Castaic Clay Products LLC

Castaic · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Cosmic Plastics Inc

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Los Angeles · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Del West Engineering

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Flavor Producers LLC

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Hasley Canyon CHU

Castaic · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Hydro Systems Inc

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

ITT Aerospace Controls

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

L3 TECHNOLOGIES INC

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Lakeside Boats Inc

Castaic · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

LIEF ORGANICS LLC

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Lockwood Industries LLC dba Fralock

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Murphy Wall Products International

Castaic · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

MW SAUSSE & CO INC

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Pacific Metal Stampings Inc

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

REGENT AEROSPACE CORPORATION

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Robertos Boat Repair

Castaic · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Specialty Motors

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Castaic · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

The Termo Company Oak Canyon

Castaic · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Triumph Actuation Systems

Valencia · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

USPS Santa Clarita VMF

Santa Clarita · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

VAV PLASTICS Inc

Valencia · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Wayside Honor Rancho

Castaic · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Facility records are official Industrial General Permit registrations, but the association between a facility and this waterbody is derived geographically (proximity or shared HUC12 subwatershed) and is not a Water Board receiving-water determination. Where a permit carries a Water Board-stated TMDL requirement naming this water, it is listed separately above.