← Impaired waters

Waterbody profile

Official Water Board record · 2026 cycle

Arroyo Mocho

Waterbody ID (WBID)
CAR2043008020010905115519
County / counties
Alameda, Santa Clara
Regional Water Board
Regional Board 2 - San Francisco Bay Region
Waterbody type
River & Stream
Condition category
Category 5 — 303(d) listed, TMDL required
Integrated Report cycle
2026

303(d) listings (6)

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 Cause154212List on 303(d) list (TMDL required list)Revised5A TMDL still requiredLow
DiazinonPesticides141745Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)Revised5B Addressed by USEPA-approved TMDLSan Francisco Bay Urban Creeks Diazinon
EutrophicationNutrients154554List on 303(d) list (TMDL required list)Revised5A TMDL still requiredLow
pHOther Cause141759List on 303(d) list (TMDL required list)Revised5A TMDL still requiredLow
Temperature, waterOther Cause141765Do Not Delist from 303(d) list (TMDL required list)Revised5A TMDL still requiredLow
ToxicityTotal Toxics141767List on 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
CAR2043008020010905115519
CALWNUM
2204.300301, 2204.300302, 2204.300303, 2204.300900
WBD code
180500040301, 180500040302, 180500040503
Geometry
Official Water Board GIS (CA_WATERBOARDS_GIS_FINAL_2026)

Location

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

Loading map…
Watershed
Assessed size
34.78 Miles

Facilities with an NAL exceedance for a listed pollutant (3)

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

Gillig LLC2 01I027313

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

Oldcastle Infrastructure2 01I000434

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

Pleasanton Garbage Service Inc2 01I026317

pH · most recent exceedance RY 2022 · 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
Adams Pool Solutions

Pleasanton · Notice of Intent · 0.90 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Amazon com Services LLC DFA9

Dublin · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Atlantis Warehouse

Livermore · Notice of Non-Applicability · 0.45 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Bent Creek Winery

Livermore · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Big White House LLC

Livermore · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Bio Rad Laboratories

Pleasanton · No Exposure Certification · 0.24 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Carl Zeiss Inc

Dublin · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Central Concrete Supply Inc

Pleasanton · Notice of Intent · 0.31 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

CooperVision Inc

Pleasanton · No Exposure Certification · 0.86 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

DHL

Livermore · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Discovery Warehouse

Livermore · Notice of Non-Applicability · 0.90 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Draexlmaier Automotive of America LLC

Livermore · Notice of Intent · 0.35 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Gillig LLC

Livermore · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Madison Vineyards Inc

Livermore · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Oldcastle Infrastructure

Pleasanton · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

OMRON Robotics and Safety Technologies

Pleasanton · No Exposure Certification · 0.51 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Pleasanton Garbage Service Inc

Pleasanton · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Pleasanton Warehouse

Pleasanton · Notice of Non-Applicability · 0.44 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Retzlaff Vineyards

Livermore · No Exposure Certification · 0.29 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Right Away Ready Mix Pleasanton

Pleasanton · Notice of Intent · 0.04 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Rock Roll Auto Recycling

Pleasanton · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

TAEC Inc

Pleasanton · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Thermo Fisher Scientific

Pleasanton · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Thoratec LLC

Pleasanton · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Wente Vineyards Estate Winery

Livermore · Notice of Intent · 0.97 km away

derived_receiving_water

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.