Waterbody profile

Official Water Board record · 2026 cycle

Siphon Reservoir (Orange County)

Waterbody ID (WBID): CAL8011100020210722036990
County / counties: Orange
Regional Water Board: Regional Board 8 - Santa Ana Region
Waterbody type: Lake & Reservoir
Condition category: Category 5 — 303(d) listed, TMDL required
Integrated Report cycle: 2026

303(d) listings (1)

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
pHOther Cause	133908	List on 303(d) list (TMDL required list)	Revised	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: Aug 21, 2026, 12:44 AM UTC
Waterbody ID: CAL8011100020210722036990
CALWNUM: 4801.11
WBD code: 180702040103
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: 23.53 Acres

Facilities with an NAL exceedance for a listed pollutant (19)

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

ACD LLC8 30I027856

pH · most recent exceedance RY 2021 · association: derived watershed association

Aluminum Precision Products8 30I004913

pH · most recent exceedance RY 2018 · association: derived watershed association

Avon Protection Systems Inc8 30I028539

pH · most recent exceedance RY 2020 · association: derived watershed association

Bowerman Power LFG LLC8 30I026433

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

Durabag Co Inc8 30I022631

pH · most recent exceedance RY 2015 · association: derived watershed association

Electrolurgy Inc8 30I009573

pH · most recent exceedance RY 2018 · association: derived watershed association

GCP Applied Technologies Inc8 30I026390

pH · most recent exceedance RY 2020 · association: derived watershed association

Graphic Packaging International Inc8 30I021957

pH · most recent exceedance RY 2018 · association: derived watershed association

Imuraya USA inc8 30I027304

pH · most recent exceedance RY 2018 · association: derived watershed association

JWC ENVIRONMENTAL INC8 30I028134

pH · most recent exceedance RY 2020 · association: derived watershed association

LGM Pharma Solutions LLC8 30I028907

pH · most recent exceedance RY 2024 · association: derived watershed association

Maruchan Inc8 30I025984

pH · most recent exceedance RY 2022 · association: derived watershed association

Mitsubishi Chemical Carbon Fiber and Composites Inc8 30I009877

pH · most recent exceedance RY 2022 · association: derived watershed association

OC John Wayne Airport8 30I005741

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

OCTA Construction Circle8 30I021186

pH · most recent exceedance RY 2025 · association: derived watershed association

Parker Hannifin Corp8 30I005869

pH · most recent exceedance RY 2021 · association: derived watershed association

Secure Communication Systems Inc8 30I029948

pH · most recent exceedance RY 2022 · association: derived watershed association

Tibbetts Newport Corp8 30I023452

pH · most recent exceedance RY 2019 · association: derived watershed association

Toyota Racing Development USA Inc8 30I016707

pH · most recent exceedance RY 2018 · 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

3M Irvine Dental

Irvine · Notice of Intent

derived_watershed_association