California Stormwater Intelligence
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Waterbody profile

Official Water Board record · 2026 cycle

Topanga Beach

Waterbody ID (WBID)
CAX4041300019990924081553
County / counties
Los Angeles
Regional Water Board
Regional Board 4 - Los Angeles Region
Waterbody type
Coastal & Bay Shoreline
Condition category
Category 4a — TMDL completed
Integrated Report cycle
2026

303(d) listings (3)

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

Pollutant / stressorDecision IDFinal listing decisionDecision statusTMDL requirement statusTMDL projectTMDL priority
DDT (Dichlorodiphenyltrichloroethane)Pesticides70919List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLSanta Monica Bay Historic Pesticides (58)—
Indicator BacteriaPathogens68231Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLSanta Monica Bay Beach Closures/Coliform/Bacteria Indicators (48)—
PCBs (Polychlorinated biphenyls)Toxic Organics69276List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLSanta Monica Bay Historic Pesticides (58)—

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, 10:57 PM UTC
Waterbody ID
CAX4041300019990924081553
CALWNUM
4404.110000, 4404.120000, 4404.130000, 4404.140000, 4404.150000, 4404.160000, 4404.500000
WBD code
180701040401, 180701040403
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
2.53 Miles

Derived facility associations

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

Derived
ARMC Santa Monica

Santa Monica · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Big Blue Bus City of Santa Monica

Santa Monica · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Fedex SMOA

Marina Del Rey · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Nanofilm

Thousand Oaks · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Santa Monica Airport

Santa Monica · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Santa Monica Maintenance Yard

Santa Monica · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

SCD Recycling Transfer Station

Santa Monica · 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.