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Industrial stormwater facility

Sierra Alloys Co Inc

4 19I023509 · Notice of Intent · Irwindale, Los Angeles

Official record — State Water Resources Control Board, Industrial General Permit

Official

Facility record

Facility name
Sierra Alloys Co Inc
WDID
4 19I023509
Application type
Notice of Intent
City
Irwindale
County
Los Angeles
ZIP
91706
Primary SIC code
3399
SIC description
Primary Metal Products, NEC
Date active
2012-02-08
Regional Water Board
Regional Board 4 - Los Angeles Region

Hydrologic

Geographic context

Official facility coordinate plotted against the official 2026 impaired-water geometry.

Official facility point
34.11220, -117.92960
HUC12 subwatershed
Big Dalton Wash
HUC12 code
180701060402
Impaired-water associations (derived)
5
Loading map…

303(d) context

Associated impaired waters

Grouped by derived geographic association class.

Derived

Same impaired-water subwatershed

5 waterbodies
Little Dalton Wash

River & Stream · Integrated Report category 5 · TMDL required

Listed pollutants / stressors (5) alpha-Endosulfan (Endosulfan 1), Copper, Indicator Bacteria, Lead, Zinc

Distance

Confidence low

Fact sheet

Live Oak Wash

River & Stream · Integrated Report category 5 · TMDL required

Listed pollutants / stressors (2) Copper, Indicator Bacteria

Distance

Confidence low

Fact sheet

Puddingstone Reservoir

Lake & Reservoir · Integrated Report category 5 · TMDL required

Listed pollutants / stressors (5) Chlordane, DDT (Dichlorodiphenyltrichloroethane), Mercury, Organic Enrichment/Low Dissolved Oxygen, PCBs (Polychlorinated biphenyls)

Distance

Confidence low

Fact sheet

San Dimas Wash (Los Angeles County)

River & Stream · Integrated Report category 5 · TMDL required

Listed pollutants / stressors (3) Copper, Indicator Bacteria, Zinc

Distance

Confidence low

Fact sheet

Walnut Creek Wash (Drains from Puddingstone Res)

River & Stream · Integrated Report category 5 · TMDL required

Listed pollutants / stressors (4) Benthic Community Effects, Copper, Indicator Bacteria, pH

Distance

Confidence low

Fact sheet

Associations are calculated from official facility coordinates, USGS HUC12 boundaries, and official 2026 impaired-water geometry. They do not establish a discharge connection or causation.

TMDL requirements

Water Board-stated TMDL waste load allocations applied to this industrial permit in SMARTS.

Official record — SMARTS TMDL dataset, State Water Board

No SMARTS TMDL requirement is recorded for this WDID. In the statewide TMDL export only permits in Regions 4, 8 and 9 currently carry industrial TMDL requirements, so an absence here is not a statement that the facility discharges to an unimpaired water.

Official monitoring

SMARTS monitoring

Self-reported industrial stormwater sampling results as submitted by the discharger to SMARTS.

Official record — SMARTS parameter data, State Water Board
Reported results
408
Sample events
58
Distinct parameters
11
Reporting years
2015 – 2025
First sample
2016-03-11
Latest sample
2026-02-16
Source regional dataset
Region 4 - Los Angeles
Source retrieved
Aug 21, 2026

Official SMARTS public reports

Parameters reported

Reported results over time

Loading reported results…

Most recent reported results

Latest 25 of 408
Sample dateLocationParameterResultUnitsEvent
2026-02-16WaterfrontAluminumND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterfrontChromiumND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterfrontIronND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterfrontNickelND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterfrontNitrate/Nitrite (Nitrite + Nitrate as N).129mg/LQualifying Storm Event
2026-02-16WaterfrontOil and GreaseND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterfrontpH6.7SUQualifying Storm Event
2026-02-16WaterfrontTotal Suspended Solids (TSS)10mg/LQualifying Storm Event
2026-02-16WaterfrontZincND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterrearAluminumND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterrearChromiumND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterrearIronND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterrearNickelND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterrearNitrate/Nitrite (Nitrite + Nitrate as N).127mg/LQualifying Storm Event
2026-02-16WaterrearOil and GreaseND (non-detect / est.)mg/LQualifying Storm Event
2026-02-16WaterrearpH7.1SUQualifying Storm Event
2026-02-16WaterrearTotal Suspended Solids (TSS)9mg/LQualifying Storm Event
2026-02-16WaterrearZincND (non-detect / est.)mg/LQualifying Storm Event
2025-11-14WaterfrontAluminum.349mg/LQualifying Storm Event
2025-11-14WaterfrontChromiumND (non-detect / est.)mg/LQualifying Storm Event
2025-11-14WaterfrontIron.386mg/LQualifying Storm Event
2025-11-14WaterfrontNickelND (non-detect / est.)mg/LQualifying Storm Event
2025-11-14WaterfrontNitrate/Nitrite (Nitrite + Nitrate as N).092mg/LQualifying Storm Event
2025-11-14WaterfrontOil and GreaseND (non-detect / est.)mg/LQualifying Storm Event
2025-11-14WaterfrontpH7.2SUQualifying Storm Event

Monitoring rows are official self-reported SMARTS submissions, joined to this facility by WDID. California Stormwater Intelligence does not restate, correct, average or evaluate reported values, and no benchmark comparison or violation determination is made.

YDOS-derived

Numeric Action Level comparison

Reported SMARTS analytical results compared against the Numeric Action Levels of the Industrial General Permit version in effect for each reporting year (July 1 – June 30).

Derived
Reporting years evaluated
10
Years with an NAL exceedance
2
Most recent evaluated year
RY 2025
Ruleset
igp_nal_ruleset_v1 / igp_nal_v1
ParameterNAL typeCalculated valueNALResultSamples usedMethod

Aluminum, Total

aluminum_total

Annual0.151 mg/L0.75 mg/LAt or below NALAnnual average of 6 eligible result(s) compared with the annual NAL.0.2× threshold6 eligible2 non-detect as zeroarithmetic mean of all eligible effluent results in the July 1 - June 30 reporting year (censored results assigned zero only where MDL and ML were both reported)

Iron, Total

iron_total

Annual0.153 mg/L1 mg/LAt or below NALAnnual average of 6 eligible result(s) compared with the annual NAL.0.15× threshold6 eligible2 non-detect as zeroarithmetic mean of all eligible effluent results in the July 1 - June 30 reporting year (censored results assigned zero only where MDL and ML were both reported)

Nickel, Total

nickel_total

Annual0 mg/l1.02 mg/lAt or below NALAnnual average of 6 eligible result(s) compared with the annual NAL.0× threshold6 eligible6 non-detect as zeroarithmetic mean of all eligible effluent results in the July 1 - June 30 reporting year (censored results assigned zero only where MDL and ML were both reported)

Nitrite Plus Nitrate (as N)

nitrate_nitrite_n

Annual0.137 mg/L as N0.68 mg/L as NAt or below NALAnnual average of 6 eligible result(s) compared with the annual NAL.0.2× threshold6 eligiblearithmetic mean of all eligible effluent results in the July 1 - June 30 reporting year (censored results assigned zero only where MDL and ML were both reported)

Oil and Grease

oil_grease

Instantaneous maximum0 samples above25 mg/LAt or below NALNo eligible result in this reporting year was outside the instantaneous maximum NAL.6 eligible6 non-detect as zerocount of eligible effluent results outside the instantaneous maximum NAL within the July 1 - June 30 reporting year

pH

ph

Instantaneous maximum0 samples above6 – 9 pH unitsWithin NAL rangeNo eligible result in this reporting year was outside the instantaneous maximum NAL.6 eligiblecount of eligible effluent results outside the instantaneous maximum NAL within the July 1 - June 30 reporting year

Total Suspended Solids (TSS)

tss

Instantaneous maximum0 samples above400 mg/LAt or below NALNo eligible result in this reporting year was outside the instantaneous maximum NAL.6 eligiblecount of eligible effluent results outside the instantaneous maximum NAL within the July 1 - June 30 reporting year

Zinc, Total

zinc_total

Annual0.041 mg/L0.26 mg/LAt or below NALAnnual average of 6 eligible result(s) compared with the annual NAL.0.16× threshold6 eligible2 non-detect as zeroarithmetic mean of all eligible effluent results in the July 1 - June 30 reporting year (censored results assigned zero only where MDL and ML were both reported)

An NAL exceedance is a permit-defined condition that triggers Exceedance Response Actions under the Industrial General Permit. It is not a violation, an enforcement action, or a Water Board compliance determination. Annual values use the arithmetic average of eligible results with non-detects treated as zero; instantaneous maximum NALs (total suspended solids, oil and grease, pH) are exceeded when two or more eligible results in a reporting year fall outside the level. Rules transcribed from 2014-0057-DWQ as amended by 2015-0122-DWQ (effective 2015-07-01, superseded 2020-06-30); 2014-0057-DWQ as amended by 2018-0028-DWQ (effective 2020-07-01).

Provenance

Source & provenance

Source agency
California State Water Resources Control Board
Source dataset
Industrial General Permit — permitted facilities (statewide GIS layer)
WDID
4 19I023509
Source feature ID
12311
Application type
Notice of Intent
Regional board derivation
WDID region prefix
Geometry status
valid
Last successful facility import
Aug 21, 2026, 1:57 AM UTC

Official IGP permitted facilities feature layer