← Impaired waters

Waterbody profile

Official Water Board record · 2026 cycle

Calleguas Creek Reach 8 (Tapo Canyon Creek)

Waterbody ID (WBID)
CAR4036700020000228151947
County / counties
Ventura
Regional Water Board
Regional Board 4 - Los Angeles Region
Waterbody type
River & Stream
Condition category
Category 5 — 303(d) listed, TMDL required
Integrated Report cycle
2026

303(d) listings (12)

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
BoronMetals76411List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Boron/Sulfate/TDS (4)—
ChlordanePesticides74036List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Historic Pesticides (5)—
ChlorideSALINITY/TOTAL DISSOLVED SOLIDS/CHLORIDES/SULFATES76688List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Chloride (3)—
ChlorpyrifosPesticides70649List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Toxicity (2)—
DDT (Dichlorodiphenyltrichloroethane)Pesticides69406List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Historic Pesticides (5)—
DiazinonPesticides74037List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Toxicity (2)—
DieldrinPesticides69407List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Historic Pesticides (5)—
PCBs (Polychlorinated biphenyls)Toxic Organics70293List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek PCBs (7)—
Sedimentation/SiltationSediment70130List on 303(d) list (TMDL required list)Original5A — TMDL still required—Low
SulfatesToxic Inorganics76365Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Boron/Sulfate/TDS (4)—
Total Dissolved SolidsSALINITY/TOTAL DISSOLVED SOLIDS/CHLORIDES/SULFATES76115Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Boron/Sulfate/TDS (4)—
ToxaphenePesticides68947List on 303(d) list (being addressed by USEPA approved TMDL)Original5B — Addressed by USEPA-approved TMDLCalleguas Creek Historic Pesticides (5)—

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
CAR4036700020000228151947
CALWNUM
4408.260000, 4408.270000
WBD code
180701030101, 180701030102
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
7.3 Miles

Derived facility associations

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

Derived
133art LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

3D Lettering Corp

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Advanced Metal MFG INC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

AeroVironment Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

AeroVironment Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

AeroVironment Inc

Moorpark · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Amazon com Services LLC DCX6

Moorpark · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Amazon com Services LLC DPS2

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Amazon com Services LLC DPS6

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

AMR Medic 431

Simi Valley · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

Apollo Express

Simi Valley · Notice of Non-Applicability · 0.03 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Automotive Designs and Fabrication

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Bemco Incorporated

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Boiron Incorporated

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Boregyde Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Bourdelais Grinding

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

BWE Manufacturing LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

BWE Manufacturing LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

BWE Manufacturing LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

C & M Topsoil Inc Tapo Processing Yard

Simi Valley · Notice of Intent · 0.73 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

California Lasers Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Chatsworth Products

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

CineMag Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Circuit Express

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

City of Simi Valley

Simi Valley · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

CJS Woodworking and Design

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

CM Ammo and Firearm Supply

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Computer Metal Products Corp

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Cooking with The Captain Sourdough

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

CRV ONLY STORE INC

Simi Valley · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

CS Circuits

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Datron Advanced Tech Div

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

DELT INDUSTRIES INC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

DR Circuits LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Edge Racing West Coast Division

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

EMLinQ LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

ENDERLE FUEL INJECTION

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Ensign Bickford A and D Company

Moorpark · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Entech Instruments Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

ESI

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Fast Intnetions Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Fermionics Opto Technology

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

FIBEROPTIC SYSTEMS INC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

FIBEROPTIC SYSTEMS INC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Freedom Designs Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Frontier Electronics Corporation

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

FRONTLINE FREIGHT & FULFILLMENT

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

gas powder coating

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

General Research Labs Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

GenRight Off Road Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

GI Industries

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

GT Design and Graphics Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Industrial Street West Valley Yard

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Infinity Precision Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Innovative Tube Design

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Interscan Corporation

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Jaxx Manufacturing Incorporated

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

LEE AEROSPACE PRODUCTS INC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Lion Heart Mfg

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

M Wave Design Corporation

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

M Wave Design Corporation

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Maia Products Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Meggitt Safety Systems Inc

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Metalcrafters

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Mike Willard Automotive

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Milgard Manufacturing Inc

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

MKSPECTRACOLOR INC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Mold Precision Engineering Inc

Simi · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Northridge Moving Storage Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Nut Butter Concepts LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Oak Park Big Mountain Field

Moorpark · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Omegasonics

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Pentair Offsite Warehouse

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Peppertree Business Park

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Pharmaceutic Litho and Label Co

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Pierson Industries Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Piezo Metrics Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Platt Designs Inc

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

PLI Warehouse

Simi Valley · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

Poly Tainer Inc

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Powerhouse

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Pre Con Products

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Proto Works Machining LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

PSI Bearings

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

PW Gillibrand Co Simi Valley

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

RFP Welding

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Ricoh Printing Systems

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Robertsons Simi Valley Batch Plant

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Rovi Products Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

ROYAL COATINGS

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

RSA Engineered Products LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

S2K Graphics

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Savage Machining Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

SCIENTIFIC CUTTING TOOLS INC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Scribners Ink

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Sheetmetal Engineering Incorporated

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Shred It Moorpark

Moorpark · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Simi Commerce Center

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Simi Valley

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Simi Valley - Stearns Street (1015)

Simi Valley · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

Simi Valley Landfill

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Simi Valley Ready Mix

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Simi Valley Unified School District Transportation Yard

Simi Valley · Notice of Intent · 0.35 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Sosas Mfg

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Specialty Fabrications Incorporated

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Spex Graphics, Inc.

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Spragues Ready Mix

Simi Valley · Notice of Intent · 0.02 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Tapo Rock Sand

Simi Valley · Notice of Intent · 0.89 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

TForce Freight Simi Valley

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

The Research Council of Makeup Artists Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

UDASH Inc

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Underground Soap Lady

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Vanderhorst Brothers Inc

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Vans Manufacturing Incorporated

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Vista Professional Outdoor Lighting Bld 2

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Vista Professional Outdoor Lighting Blds 1&3

Simi Valley · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Westport LRLP Simi Valley LLC

Simi Valley · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

WSM Investment LLC

Simi Valley · No Exposure Certification

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.