Mattco Forge Inc
Active WDID 4 19I025496 Paramount, Los Angeles County Region 4 · Los Angeles
At a glance
- Permit Evidence: SMARTS record
- Active Industrial
- Notice of Intent (WDID code I) · Permits and applications
- Location Evidence: facility-reported
- Paramount, Los Angeles County
- Region 4 · Los Angeles · Location · Statewide map
- Receiving water
- Los Angeles River (as reported by the facility)
- Evidence: candidate, awaiting review Details
- Identified receiving water on the 2026 303(d) list
- Not established
- Shown only when the reported receiving water is identified and corroborated.
- 2026 Integrated Report waters within 1.0 km Evidence: geographic proximity
- None
- Monitoring results Evidence: facility-reported
- 718 distinct results, 10 reporting years (2016 to 2025)
- Most recent sample Mar 31, 2026 · Monitoring
- Compliance and enforcement records Evidence: SMARTS record
- 1 inspection · 9 violation records · 5 enforcement actions
- Counts as published in SMARTS; not a compliance determination · Details
Each label shows where a statement comes from. How to read the labels.
Overview and location
Reported facility location HUC12 watershed Corroborated receiving water 2026 Integrated Report waterbodies nearby
Reported location Evidence: facility-reported
- Coordinates
- 33.88923, -118.16669
- Precision
- 5 decimal places
- Shared point
- No
- Matches application record
- same
Facility location as reported by the discharger in SMARTS; not a discharge point or outfall.
- Facility address
- 16443 Minnesota Ave and 7530 Jackson Street, Paramount 90723
- Regional Water Board
- 4 — Los Angeles
HUC12 watershed Evidence: spatial
- Compton Creek-Los Angeles River HUC12 180701050402
The facility's reported location lies within this HUC12 watershed (spatial derivation); it is not a discharge location.
Permits and applications Evidence: SMARTS record
Current permit record
- Permit type
- Industrial
- Application type
- Notice of Intent (WDID code I)
- Status
- Active
- Operator
- Mattco Forge Inc
- Primary industry (SIC)
- 3462-Iron and Steel Forgings
- Application ID
- 455571
- NOI processed
- May 27, 2015
- Last certified
- Jul 11, 2022
- Facility size
- 4 Acres
- Impervious area
- 1 %
Retrieved from SMARTS Oct 20, 2026. Verify against SMARTS before relying on it.
Permit history
| Application | Type | Status | Processed | Terminated | Certified |
|---|---|---|---|---|---|
| 455571 | Industrial | Active | May 27, 2015 | — | Jul 11, 2022 |
Every storm water application SMARTS records for this WDID, newest first (1).
Receiving water
- Reported by the facility Evidence: facility-reported
- Los Angeles River
- Discharges directly / indirectly
- N / Y (as answered in the permit application)
Evidence: not confirmed Evidence: candidate, awaiting review Awaiting review
Receiving-water text as reported by the discharger in SMARTS; no waterbody identification has been confirmed.
Why it is not confirmed (1)
- C1 name is only a prefix of official names
7 official waterbodies share this name; none is assigned without review.
Impaired waters and TMDLs
Two kinds of information, kept apart: 2026 Integrated Report waterbodies near the reported location (geographic proximity only), and TMDL records that SMARTS lists for this facility. Neither establishes where the facility discharges; see Receiving water for the facility's own statement.
Nearby waterbodies Evidence: geographic proximity
Spatial proximity only; discharge pathway not established. Being near a waterbody does not mean the facility discharges to it.
No 2026 Integrated Report waterbody lies within the proximity threshold of the reported location.
SMARTS TMDL records Evidence: SMARTS-reported
SMARTS TMDL record as reported for this facility; it is not a determination that the TMDL applies to the facility.
| TMDL | Waterbody (as reported) | Parameter | Limit | Type | Period | Due | Discharges to TMDL water |
|---|---|---|---|---|---|---|---|
| Los Angeles River Metals TMDL | Los Angeles River and Los Angeles River Tributaries | Zinc, Total | .159 mg/L | NEL instantaneous | FINAL | 2020-07-01 | Y |
| Los Angeles River Nitrogen TMDL | Los Angeles River Watershed | Nitrate, Total (as N) | 8 mg/L | NEL instantaneous | FINAL | 2020-07-01 | Y |
| Los Angeles River Nitrogen TMDL | Los Angeles River Watershed | Nitrite Plus Nitrate (as N) | 8 mg/L | NEL instantaneous | FINAL | 2020-07-01 | Y |
| Los Angeles River Nitrogen TMDL | Los Angeles River Watershed | Nitrite, Total (as N) | 1 mg/L | NEL instantaneous | FINAL | 2020-07-01 | Y |
4 records. Links between these records and specific TMDL projects or listed waterbodies have not been reviewed and are not shown.
Reported monitoring results Evidence: facility-reported
Numeric Action Level (NAL) screening is being independently validated and is not shown. Nothing on this page states whether a result exceeded a NAL.
718 distinct measurements across 16 parameters, most recent sample Mar 31, 2026.
By reporting year
| Reporting year (July–June) | Distinct results | Parameters | With several versions | First sample | Last sample |
|---|---|---|---|---|---|
| 2025 | 36 | 9 | 0 | Oct 14, 2025 | Mar 31, 2026 |
| 2024 | 9 | 9 | 0 | Feb 12, 2025 | Feb 12, 2025 |
| 2023 | 27 | 9 | 0 | Dec 20, 2023 | Feb 01, 2024 |
| 2022 | 18 | 9 | 0 | Nov 08, 2022 | Nov 08, 2022 |
| 2021 | 54 | 9 | 0 | Dec 14, 2021 | Mar 28, 2022 |
| 2020 | 60 | 15 | 0 | Dec 28, 2020 | Dec 28, 2020 |
| 2019 | 227 | 15 | 0 | Nov 20, 2019 | May 18, 2020 |
| 2018 | 195 | 13 | 0 | Jan 14, 2019 | Mar 06, 2019 |
| 2017 | 56 | 7 | 0 | Jan 09, 2018 | Mar 22, 2018 |
| 2016 | 36 | 8 | 0 | Jan 20, 2017 | Feb 17, 2017 |
By parameter
| Parameter | Units | Measurements | Below detection | First sample | Last sample | Results |
|---|---|---|---|---|---|---|
| Aluminum, Total | mg/L | 67 | 3 | Jan 20, 2017 | Mar 31, 2026 | Results |
| Iron, Total | mg/L | 67 | 6 | Jan 20, 2017 | Mar 31, 2026 | Results |
| pH | SU | 67 | 0 | Jan 20, 2017 | Mar 31, 2026 | Results |
| Zinc, Total | mg/L | 67 | 1 | Jan 20, 2017 | Mar 31, 2026 | Results |
| Nitrite Plus Nitrate (as N) | mg/L | 66 | 12 | Jan 20, 2017 | Mar 31, 2026 | Results |
| Total Suspended Solids (TSS) | mg/L | 65 | 1 | Jan 20, 2017 | Mar 31, 2026 | Results |
| Oil and Grease | mg/L | 62 | 29 | Jan 20, 2017 | Mar 31, 2026 | Results |
| Cobalt, Total | mg/L | 38 | 16 | Jan 14, 2019 | Dec 28, 2020 | Results |
| Lead, Total | mg/L | 38 | 3 | Jan 14, 2019 | Dec 28, 2020 | Results |
| Nickel, Total | mg/L | 38 | 1 | Jan 14, 2019 | Dec 28, 2020 | Results |
| Titanium, Total | mg/L | 38 | 1 | Jan 14, 2019 | Dec 28, 2020 | Results |
| Magnesium, Total | mg/L | 32 | 0 | Jan 14, 2019 | Dec 28, 2020 | Results |
Show 4 more parameters
| Parameter | Units | Measurements | Below detection | First sample | Last sample | Results |
|---|---|---|---|---|---|---|
| Chromium (VI) | ug/L | 24 | 20 | Jan 14, 2019 | Dec 28, 2020 | Results |
| Nitrate, Total (as N) | mg/L | 24 | 6 | May 18, 2020 | Mar 31, 2026 | Results |
| Nitrite, Total (as N) | mg/L | 24 | 10 | May 18, 2020 | Mar 31, 2026 | Results |
| Copper, Total | mg/L | 1 | 0 | Jan 20, 2017 | Jan 20, 2017 | Results |
All results (718 distinct rows)
| Sample date | Parameter | Result | Units | Location type | Event | Method | Report | Versions |
|---|---|---|---|---|---|---|---|---|
| Mar 31, 2026 | Aluminum, Total | .14 | mg/L | Effluent | Qualifying Storm Event | E200.8 | 1371313 | |
| Mar 31, 2026 | Iron, Total | ND | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1371313 | |
| Mar 31, 2026 | Nitrate, Total (as N) | .17 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1371313 | |
| Mar 31, 2026 | Nitrite Plus Nitrate (as N) | .38 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1371313 | |
| Mar 31, 2026 | Nitrite, Total (as N) | .21 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1371313 | |
| Mar 31, 2026 | Oil and Grease | 1.4 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1371313 | |
| Mar 31, 2026 | pH | 6 | SU | Effluent | Qualifying Storm Event | pH_Paper | 1371313 | |
| Mar 31, 2026 | Total Suspended Solids (TSS) | 2.9 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1371313 | |
| Mar 31, 2026 | Zinc, Total | .061 | mg/L | Effluent | Qualifying Storm Event | E200.8 | 1371313 | |
| Feb 16, 2026 | Aluminum, Total | .87 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1360925 | |
| Feb 16, 2026 | Iron, Total | ND | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1360925 | |
| Feb 16, 2026 | Nitrate, Total (as N) | DNQ .097 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1360925 | |
| Feb 16, 2026 | Nitrite Plus Nitrate (as N) | DNQ .097 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1360925 | |
| Feb 16, 2026 | Nitrite, Total (as N) | ND | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1360925 | |
| Feb 16, 2026 | Oil and Grease | 1.4 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1360925 | |
| Feb 16, 2026 | pH | 6 | SU | Effluent | Qualifying Storm Event | pH_Paper | 1360925 | |
| Feb 16, 2026 | Total Suspended Solids (TSS) | 3.3 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1360925 | |
| Feb 16, 2026 | Zinc, Total | DNQ .053 | mg/L | Effluent | Qualifying Storm Event | E200.8 | 1360925 | |
| Nov 14, 2025 | Aluminum, Total | .085 | mg/L | Effluent | Qualifying Storm Event | E200.8 | 1360204 | |
| Nov 14, 2025 | Iron, Total | ND | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1360204 | |
| Nov 14, 2025 | Nitrate, Total (as N) | .35 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1360204 | |
| Nov 14, 2025 | Nitrite Plus Nitrate (as N) | .49 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1360204 | |
| Nov 14, 2025 | Nitrite, Total (as N) | .14 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1360204 | |
| Nov 14, 2025 | Oil and Grease | 1.2 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1360204 | |
| Nov 14, 2025 | pH | 6 | SU | Effluent | Qualifying Storm Event | pH_Paper | 1360204 | |
| Nov 14, 2025 | Total Suspended Solids (TSS) | 1.2 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1360204 | |
| Nov 14, 2025 | Zinc, Total | .26 | mg/L | Effluent | Qualifying Storm Event | E200.8 | 1360204 | |
| Oct 14, 2025 | Aluminum, Total | .25 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1355062 | |
| Oct 14, 2025 | Iron, Total | .84 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1355062 | |
| Oct 14, 2025 | Nitrate, Total (as N) | .82 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1355062 | |
| Oct 14, 2025 | Nitrite Plus Nitrate (as N) | ND | mg/L | Effluent | Qualifying Storm Event | A4500NE | 1355062 | |
| Oct 14, 2025 | Nitrite, Total (as N) | ND | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1355062 | |
| Oct 14, 2025 | Oil and Grease | 1.8 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1355062 | |
| Oct 14, 2025 | pH | 6 | SU | Effluent | Qualifying Storm Event | pH_Paper | 1355062 | |
| Oct 14, 2025 | Total Suspended Solids (TSS) | 3.6 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1355062 | |
| Oct 14, 2025 | Zinc, Total | .52 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1355062 | |
| Feb 12, 2025 | Aluminum, Total | .17 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1322082 | |
| Feb 12, 2025 | Iron, Total | DNQ .4 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1322082 | |
| Feb 12, 2025 | Nitrate, Total (as N) | DNQ .07 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1322082 | |
| Feb 12, 2025 | Nitrite Plus Nitrate (as N) | DNQ .07 | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1322082 | |
| Feb 12, 2025 | Nitrite, Total (as N) | ND | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1322082 | |
| Feb 12, 2025 | Oil and Grease | DNQ .84 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1322082 | |
| Feb 12, 2025 | pH | 6 | SU | Effluent | Qualifying Storm Event | pH_Paper | 1322082 | |
| Feb 12, 2025 | Total Suspended Solids (TSS) | DNQ 2.1 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1322082 | |
| Feb 12, 2025 | Zinc, Total | .21 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1322082 | |
| Feb 01, 2024 | Aluminum, Total | .099 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1273680 | |
| Feb 01, 2024 | Aluminum, Total | .093 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1276931 | |
| Feb 01, 2024 | Iron, Total | .16 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1273680 | |
| Feb 01, 2024 | Iron, Total | .058 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1276931 | |
| Feb 01, 2024 | Nitrate, Total (as N) | ND | mg/L | Effluent | Qualifying Storm Event | E300.0 | 1273680 |
Results are shown exactly as reported by the discharger. Identical rows repeated in the State's export are shown once. Where the export contains different versions of the same sample and parameter, each version is listed and flagged. Details.
Compliance and enforcement records Evidence: SMARTS record
These are records as the State Water Board publishes them in SMARTS, with the source's own types and statuses. They are not a compliance determination or rating. A record listed here is not proof of a violation beyond what the source states, and the absence of records does not establish compliance.
| Record type | Records | As published | Dates | Retrieved | List |
|---|---|---|---|---|---|
| Violations | 9 | 7 Violation · 0 Potential (preliminary) · 2 Dismissed | Feb 04, 2022 – Dec 20, 2023 | Oct 21, 2026 | All violations |
| Enforcement actions | 5 | 3 issued · 0 draft · 2 withdrawn, rescinded or superseded | Mar 07, 2022 – Dec 20, 2023 | Oct 21, 2026 | All actions |
| Inspections | 1 | inspections, not findings | Feb 04, 2022 – Feb 04, 2022 | Oct 21, 2026 | All inspections |
| Annual reports | 11 | certified reports (contents not shown) | 2015 – 2025 | Oct 21, 2026 | All reports |
| Water-quality-based corrective action reports | 2 | reports, by parameter | 2021-22 – 2022-23 | Oct 21, 2026 | All reports |
Each record type is counted by its own SMARTS identifier. A violation and the enforcement action that cites it are two records in two lists; they are never added together.
Chronological record history (28 records, newest first)
| Date | Record | ID | Type or purpose | Status as published | Detail |
|---|---|---|---|---|---|
| Jun 30, 2026 | Annual reports | 1339552 | Annual report 2025 | — | |
| Jul 08, 2025 | Annual reports | 1298616 | Annual report 2024 | — | |
| Jun 13, 2024 | Annual reports | 1247909 | Annual report 2023 | — | |
| Feb 06, 2024 | Water-quality-based corrective action reports | 1274350 | WQBCAR 2021-22 | — | Zinc, Total |
| Dec 20, 2023 | Enforcement actions | 452536 | ACL (Administrative Civil Liability) | Historical | R4-2023-0380 |
| Dec 20, 2023 | Violations | 887710 | Effluent | Violation | Report |
| Dec 20, 2023 | Violations | 887711 | Effluent | Violation | Report |
| Dec 20, 2023 | Violations | 887712 | Effluent | Violation | Report |
| Dec 20, 2023 | Violations | 887714 | Late Report | Violation | Report |
| Jul 13, 2023 | Annual reports | 1194135 | Annual report 2022 | — | |
| Jul 13, 2023 | Water-quality-based corrective action reports | 1239875 | WQBCAR 2022-23 | — | Zinc, Total |
| Aug 31, 2022 | Enforcement actions | 447128 | NOV (Notice of Violation) | Historical | |
| Aug 31, 2022 | Violations | 882483 | Deficient Report | Violation | Report |
| Jul 14, 2022 | Annual reports | 1118054 | Annual report 2021 | — | |
| Jun 02, 2022 | Enforcement actions | 446615 | NOV (Notice of Violation) | Withdrawn | |
| Jun 02, 2022 | Violations | 881838 | Late Report | Dismissed | Report |
| Mar 16, 2022 | Enforcement actions | 446233 | NOV (Notice of Violation) | Withdrawn | |
| Mar 16, 2022 | Violations | 881437 | Late Report | Dismissed | Report |
| Mar 07, 2022 | Enforcement actions | 446786 | Verbal Communication | Historical | |
| Feb 04, 2022 | Inspections | 2056860 | B Type compliance | Finalized | Additional Info Required |
| Feb 04, 2022 | Violations | 882028 | Incomplete/Insufficient SWPPP | Violation | Inspection |
| Feb 04, 2022 | Violations | 882029 | Deficient BMP Implementation | Violation | Inspection |
| Sep 16, 2021 | Annual reports | 1066311 | Annual report 2020 | — | |
| Jul 13, 2020 | Annual reports | 983452 | Annual report 2019 | — | |
| Jul 15, 2019 | Annual reports | 959829 | Annual report 2018 | — |
Sources and provenance
| Information | Source | Retrieved or published |
|---|---|---|
| Permit, location, receiving-water text | SMARTS Industrial Application Specific Data | Oct 20, 2026 |
| Permit history | SMARTS Storm Water Applications | Oct 20, 2026 |
| Monitoring results | SMARTS Industrial Parameter Data | Oct 20, 2026 |
| Watershed Boundary Dataset HU2 GeoPackages 15, 16, 18 (WBDHU12) | USGS | 2026-10-22 |
| 2026 California Integrated Report, Appendix A: 2026 303(d) List (final) | SWRCB | 2026-10-22 |
| Final_2026_Rivers_and_Streams + Final_2026_Lakes_and_Reservoirs (FeatureServer 0) | SWRCB GIS | 2026-10-22 |
| SMARTS TMDL requirements | SMARTS | 2026-10-21 |
Relationships computed 2026-10-22 with methods facility_huc12/1, proximity/1, receiving_water/2, tmdl_reference/1, waterbody_huc12_ovl/1, waterbody_huc12_pub/1; proximity threshold 1.0 km.
How to read the evidence labels
- Evidence: SMARTS record Evidence: facility-reported Information as published in SMARTS or reported by the discharger.
- Evidence: identification corroborated The reported receiving-water name identifies one official waterbody and the facility's location is consistent with it. It does not establish a discharge pathway.
- Evidence: candidate, awaiting review Evidence: not confirmed The reported name could match one or more official waterbodies, but no identification has been confirmed; nothing is assigned without review.
- Evidence: spatial Evidence: geographic proximity Derived from the reported location only.
- Evidence: SMARTS-reported Source records whose links to official references are not yet reviewed.
- Evidence: unavailable The information could not be loaded or is not in the sources.
Records are shown as published and are not compliance determinations. How geographic context is derived.