Serrano Creek

Waterbody ID (WBID): CAR8011100020080921203908
County / counties: Orange
Regional Water Board: Regional Board 8 - Santa Ana 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 / stressor	Decision ID	Final listing decision	Decision status	TMDL requirement status	TMDL project	TMDL priority
Ammonia (Unionized)Nutrients	73597	Do Not Delist from 303(d) list (TMDL required list)	Original	5A — TMDL still required	—	Low
Benthic Community EffectsOther Cause	152851	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
Indicator BacteriaPathogens	149178	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
pHOther Cause	133307	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
ToxicityTotal Toxics	96449	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: Aug 21, 2026, 12:44 AM UTC
Waterbody ID: CAR8011100020080921203908
CALWNUM: 4801.11
WBD code: 180702040102
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: 7.44 Miles

Facilities with an NAL exceedance for a listed pollutant (5)

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

Dynacast Inc8 30I014348

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

Frank R Bowerman Landfill8 30I005261

pH · most recent exceedance RY 2017 · association: derived watershed association

Irvine Distribution Ctr 363118 30I024269

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

OCTA Irvine8 30I002221

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

Parker Hannifin Corp8 30I017123

pH · most recent exceedance RY 2017 · association: derived nearby in watershed

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

A&J Manufacturing Company

Foothill Ranch · No Exposure Certification · 0.65 km away

derived_receiving_water