Walnut Ready Mix
Active WDID 4 19I004088 Walnut, 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
- Walnut, Los Angeles County
- Region 4 · Los Angeles · Location · Statewide map
- Receiving water
- San Jose Creek (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
- 1 waterbody; 1 on the 2026 303(d) list
- Proximity only; not a discharge pathway · Nearby waterbodies
- Monitoring results Evidence: facility-reported
- 17 distinct results, 3 reporting years (2015 to 2017)
- Most recent sample Jan 09, 2018 · Monitoring
- Compliance and enforcement records Evidence: SMARTS record
- 3 inspections · 10 violation records · 4 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
- 34.00829, -117.84913
- 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
- 20903 Currier Rd, Walnut 91789
- Regional Water Board
- 4 — Los Angeles
HUC12 watershed Evidence: spatial
- Upper San Jose Creek HUC12 180701060501
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
- Cemex Construction Materials Pacific LLC
- Primary industry (SIC)
- 3273-Ready-Mixed Concrete
- Application ID
- 189289
- NOI processed
- Apr 06, 1992
- Last certified
- Mar 12, 2019
- Facility size
- 2 Acres
- Impervious area
- 100 %
Retrieved from SMARTS Oct 20, 2026. Verify against SMARTS before relying on it.
Permit history
| Application | Type | Status | Processed | Terminated | Certified |
|---|---|---|---|---|---|
| 189289 | Industrial | Active | Apr 06, 1992 | — | Mar 12, 2019 |
Every storm water application SMARTS records for this WDID, newest first (1).
Receiving water
- Reported by the facility Evidence: facility-reported
- San Jose Creek
- 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
5 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.
| Waterbody (2026 Integrated Report) | Distance | 2026 303(d) list | Appendix A decisions |
|---|---|---|---|
| San Jose Creek Reach 1 (SG Confluence to Temple St.) CAR4053100019980918090950 | 545 m | listed | 5 |
Waterbodies within 1.0 km of the reported facility location. Method proximity/1.
SMARTS TMDL records Evidence: SMARTS-reported
No TMDL records for this facility in the SMARTS TMDL export.
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.
17 distinct measurements across 5 parameters, most recent sample Jan 09, 2018.
By reporting year
| Reporting year (July–June) | Distinct results | Parameters | With several versions | First sample | Last sample |
|---|---|---|---|---|---|
| 2017 | 5 | 5 | 0 | Jan 09, 2018 | Jan 09, 2018 |
| 2016 | 5 | 5 | 0 | Jan 19, 2017 | Jan 19, 2017 |
| 2015 | 7 | 4 | 0 | Dec 22, 2015 | Mar 07, 2016 |
By parameter
| Parameter | Units | Measurements | Below detection | First sample | Last sample | Results |
|---|---|---|---|---|---|---|
| Iron, Total | mg/L | 4 | 0 | Dec 22, 2015 | Jan 09, 2018 | Results |
| pH | SU | 4 | 0 | Dec 22, 2015 | Jan 09, 2018 | Results |
| Total Suspended Solids (TSS) | mg/L | 4 | 0 | Dec 22, 2015 | Jan 09, 2018 | Results |
| Oil and Grease | mg/L | 3 | 1 | Dec 22, 2015 | Jan 09, 2018 | Results |
| Total Dissolved Solids (TDS) | mg/L | 2 | 0 | Jan 19, 2017 | Jan 09, 2018 | Results |
All results (17 distinct rows)
| Sample date | Parameter | Result | Units | Location type | Event | Method | Report | Versions |
|---|---|---|---|---|---|---|---|---|
| Jan 09, 2018 | Iron, Total | 5.59 | mg/L | Effluent | Qualifying Storm Event | E200.8 | 994218 | |
| Jan 09, 2018 | Oil and Grease | 1.69 | mg/L | Effluent | Qualifying Storm Event | E1664A | 994218 | |
| Jan 09, 2018 | pH | 7.9 | SU | Effluent | Qualifying Storm Event | pH_Field | 994218 | |
| Jan 09, 2018 | Total Dissolved Solids (TDS) | 51 | mg/L | Effluent | Qualifying Storm Event | A2540C | 994218 | |
| Jan 09, 2018 | Total Suspended Solids (TSS) | 76.9 | mg/L | Effluent | Qualifying Storm Event | A2540D | 994218 | |
| Jan 19, 2017 | Iron, Total | 1.6 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 925926 | |
| Jan 19, 2017 | Oil and Grease | DNQ 1.92 | mg/L | Effluent | Qualifying Storm Event | E1664A | 925926 | |
| Jan 19, 2017 | pH | 7.7 | SU | Effluent | Qualifying Storm Event | pH_Field | 925926 | |
| Jan 19, 2017 | Total Dissolved Solids (TDS) | 58 | mg/L | Effluent | Qualifying Storm Event | A2540C | 925926 | |
| Jan 19, 2017 | Total Suspended Solids (TSS) | 22.2 | mg/L | Effluent | Qualifying Storm Event | A2540D | 925926 | |
| Mar 07, 2016 | Iron, Total | 9.63 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 868841 | |
| Mar 07, 2016 | pH | 8.2 | SU | Effluent | Qualifying Storm Event | A4500HB | 868841 | |
| Mar 07, 2016 | Total Suspended Solids (TSS) | 44 | mg/L | Effluent | Qualifying Storm Event | A2540D | 868841 | |
| Dec 22, 2015 | Iron, Total | 1.86 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 863142 | |
| Dec 22, 2015 | Oil and Grease | 2.51 | mg/L | Effluent | Qualifying Storm Event | E1664A | 863142 | |
| Dec 22, 2015 | pH | 8.7 | SU | Effluent | Qualifying Storm Event | pH_Field | 863142 | |
| Dec 22, 2015 | Total Suspended Solids (TSS) | 46.9 | mg/L | Effluent | Qualifying Storm Event | A2540D | 863142 |
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 | 10 | 9 Violation · 1 Potential (preliminary) · 0 Dismissed | Jul 02, 1993 – Jul 10, 2024 | Oct 21, 2026 | All violations |
| Enforcement actions | 4 | 4 issued · 0 draft · 0 withdrawn, rescinded or superseded | Dec 01, 1993 – Jul 09, 2024 | Oct 21, 2026 | All actions |
| Inspections | 3 | inspections, not findings | Dec 19, 2003 – Sep 19, 2018 | 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 | 0 | reports, by parameter | — | Oct 21, 2026 |
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 19, 2026 | Annual reports | 1335523 | Annual report 2025 | — | |
| Jul 08, 2025 | Annual reports | 1294346 | Annual report 2024 | — | |
| Jul 12, 2024 | Annual reports | 1243437 | Annual report 2023 | — | |
| Jul 10, 2024 | Violations | 889348 | Enforcement Action | Potential | Internal Report |
| Jul 09, 2024 | Enforcement actions | 453652 | 13383 Order (Water Code section 13383 order) | Historical | R4-2024-0188 |
| Jul 12, 2023 | Annual reports | 1189451 | Annual report 2022 | — | |
| Jul 06, 2022 | Annual reports | 1112842 | Annual report 2021 | — | |
| Jul 07, 2021 | Annual reports | 1068856 | Annual report 2020 | — | |
| Jul 07, 2020 | Annual reports | 986130 | Annual report 2019 | — | |
| Jul 01, 2019 | Annual reports | 953693 | Annual report 2018 | — | |
| Sep 19, 2018 | Enforcement actions | 431961 | NTC (Notice to Comply) | Historical | |
| Sep 19, 2018 | Inspections | 2040634 | B Type compliance | — | No Further Action |
| Sep 19, 2018 | Violations | 868992 | Deficient BMP Implementation | Violation | Inspection |
| Jun 26, 2018 | Annual reports | 939111 | Annual report 2017 | — | |
| Jul 12, 2017 | Annual reports | 878362 | Annual report 2016 | — | |
| May 16, 2017 | Inspections | 2034055 | B Type compliance | — | No Further Action |
| Jul 06, 2016 | Annual reports | 840978 | Annual report 2015 | — | |
| Jan 30, 2004 | Enforcement actions | 251714 | NNC (Notice of Non-Compliance) | Historical | Notice of Noncompliance |
| Dec 19, 2003 | Inspections | 2018034 | B Type compliance | — | Additional Info Required |
| Dec 19, 2003 | Violations | 251471 | Deficient Report | Violation | Inspection |
| Dec 19, 2003 | Violations | 251472 | Deficient BMP Implementation | Violation | Inspection |
| Jul 02, 1999 | Violations | 154279 | Late Report | Violation | Report |
| Jul 02, 1998 | Violations | 850877 | Late Report | Violation | Report |
| Jul 02, 1997 | Violations | 850876 | Late Report | Violation | Report |
| Jul 02, 1996 | Violations | 850875 | Late Report | Violation | Report |
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.