← Impaired waters

Waterbody profile

Official Water Board record · 2026 cycle

Arroyo Trabuco Creek, Lower

Waterbody ID (WBID)
CAR9012300020200716061934
County / counties
Orange
Regional Water Board
Regional Board 9 - San Diego Region
Waterbody type
River & Stream
Condition category
Category 5 — 303(d) listed, TMDL required
Integrated Report cycle
2026

303(d) listings (5)

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
Benthic Community EffectsOther Cause105536Do Not Delist from 303(d) list (TMDL required list)Revised5A TMDL still requiredLow
Indicator BacteriaPathogens105569Do Not Delist from 303(d) list (TMDL required list)Original5A TMDL still requiredLow
NitrogenNutrients105537Do Not Delist from 303(d) list (TMDL required list)Original5A TMDL still requiredLow
PhosphorusNutrients105535Do Not Delist from 303(d) list (TMDL required list)Original5A TMDL still requiredLow
ToxicityTotal Toxics105534Do Not Delist from 303(d) list (TMDL required list)Revised5A TMDL still requiredLow

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
Aug 21, 2026, 12:44 AM UTC
Waterbody ID
CAR9012300020200716061934
CALWNUM
4901.210000, 4901.220000, 4901.230000, 4901.270000
WBD code
180703010103, 180703010104
Geometry
Official Water Board GIS (CA_WATERBOARDS_GIS_FINAL_2026)

Location

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

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Watershed
Assessed size
16.69 Miles

Facilities with an NAL exceedance for a listed pollutant (1)

Geographically associated industrial stormwater facilities whose reported results exceeded an Industrial General Permit Numeric Action Level for a pollutant this waterbody is listed for.

Derived

Blenheim Facility Management9 30I027520

Phosphorus · most recent exceedance RY 2023 · association: derived watershed association

This is derived co-occurrence between a calculated NAL comparison and the official 303(d) listing for this waterbody. An NAL exceedance triggers Exceedance Response Actions under the permit; it is not a violation and does not establish that any facility caused or contributed to this impairment.

Derived facility associations

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

Derived
3A Treatment Plant

Laguna Niguel · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Applied Medical Resources

Rancho Santa Margarita · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Applied Medical Resources

Rancho Santa Margarita · No Exposure Certification · 0.72 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Applied Medical Resources

Rancho Santa Margarita · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Applied Medical Resources

Rancho Santa Margarita · No Exposure Certification · 0.97 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Applied Medical Resources

Rancho Santa Margarita · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Blenheim Facility Management

San Juan Capistrano · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

CRR Inc San Juan Cap

San Juan Capistrano · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

CT Organics

San Juan Capistrano · No Exposure Certification · 0.85 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Ewles Materials San Juan Cap

San Juan Capistrano · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

FaceFirst

San Juan Capistrano · No Exposure Certification · 0.73 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Forespar Products Corp

Rancho Santa Margarita · Notice of Intent · 0.69 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

IMI Critical Engineering

Rancho Santa Margarita · Notice of Intent · 0.81 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Lapeyre Industrial Sands Inc

San Juan Capistrano · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

MM Prima Deshecha Energy LLC

San Juan Capistrano · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Olsen Pavingstone Inc

San Juan Capistrano · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Oso Parkway

Laguna Hills · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

Oso Parkway Crushing Facility and Batch Plant

Mission Viejo · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Prime Fabrication

San Juan Capistrano · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Rancho Sierra Vista Equestrian Center

San Juan Capistrano · Notice of Intent · 0.13 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

San Juan Capistrano Equestrian Center

San Juan Capistrano · Notice of Intent · 0.19 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Santa Margarita Water Dist Chi

San Juan Capistrano · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Shady Maples

San Juan Capistrano · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Top Dead Center Brewery LLC

San Juan Capistrano · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

USPS Mission Viejo VMF

Mission Viejo · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Virtium LLC

Rancho Santa Margarita · No Exposure Certification · 0.56 km away

derived_nearby_in_watershed

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.