Platt Designs Inc
Active WDID 4 56I026962 Simi Valley, Ventura 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
- Simi Valley, Ventura County
- Region 4 · Los Angeles · Location · Statewide map
- Receiving water
- Arroyo Las Posas Arroyo Simi Tapo Canyon (as reported by the facility)
- Evidence: not confirmed 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
- 64 distinct results, 9 reporting years (2017 to 2025)
- Most recent sample Jan 04, 2026 · Monitoring
- Compliance and enforcement records Evidence: SMARTS record
- 1 inspection · 1 violation record · 1 enforcement action
- 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
- 34.27855, -118.79821
- 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
- 100 w Easy street, Simi Valley 93065
- Regional Water Board
- 4 — Los Angeles
HUC12 watershed Evidence: spatial
- Lower Simi Arroyo HUC12 180701030102
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
- Platt Designs Inc
- Primary industry (SIC)
- 3272-Concrete Products, Except Block and Brick
- Application ID
- 458459
- NOI processed
- Dec 16, 2016
- Last certified
- Dec 13, 2016
- Facility size
- 1 Acres
- Impervious area
- 90 %
Retrieved from SMARTS Oct 20, 2026. Verify against SMARTS before relying on it.
Permit history
| Application | Type | Status | Processed | Terminated | Certified |
|---|---|---|---|---|---|
| 458459 | Industrial | Active | Dec 16, 2016 | — | Dec 13, 2016 |
Every storm water application SMARTS records for this WDID, newest first (1).
Receiving water
- Reported by the facility Evidence: facility-reported
- Arroyo Las Posas Arroyo Simi Tapo Canyon
- Discharges directly / indirectly
- Y / N (as answered in the permit application)
Evidence: not confirmed Not matchable to a single waterbody
Receiving-water text as reported by the discharger in SMARTS; no waterbody identification has been confirmed.
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 |
|---|---|---|---|
| Calleguas Creek Reach 7 (Arroyo Simi) CAR4036200020000228103510 | 72 m | listed | 22 |
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.
64 distinct measurements across 4 parameters, most recent sample Jan 04, 2026.
By reporting year
| Reporting year (July–June) | Distinct results | Parameters | With several versions | First sample | Last sample |
|---|---|---|---|---|---|
| 2025 | 4 | 4 | 0 | Jan 04, 2026 | Jan 04, 2026 |
| 2024 | 4 | 4 | 0 | Feb 13, 2025 | Feb 13, 2025 |
| 2023 | 4 | 4 | 0 | Jan 22, 2024 | Jan 22, 2024 |
| 2022 | 8 | 4 | 0 | Nov 08, 2022 | Mar 29, 2023 |
| 2021 | 8 | 4 | 0 | Oct 25, 2021 | Jan 17, 2022 |
| 2020 | 4 | 4 | 0 | Dec 28, 2020 | Dec 28, 2020 |
| 2019 | 8 | 4 | 0 | Dec 04, 2019 | May 18, 2020 |
| 2018 | 12 | 4 | 0 | Jul 11, 2018 | Dec 07, 2018 |
| 2017 | 12 | 4 | 0 | Jan 10, 2018 | Mar 22, 2018 |
By parameter
| Parameter | Units | Measurements | Below detection | First sample | Last sample | Results |
|---|---|---|---|---|---|---|
| Iron, Total | mg/L | 16 | 0 | Jan 10, 2018 | Jan 04, 2026 | Results |
| Oil and Grease | mg/L | 16 | 9 | Jan 10, 2018 | Jan 04, 2026 | Results |
| pH | SU | 16 | 0 | Jan 10, 2018 | Jan 04, 2026 | Results |
| Total Suspended Solids (TSS) | mg/L | 16 | 9 | Jan 10, 2018 | Jan 04, 2026 | Results |
All results (64 distinct rows)
| Sample date | Parameter | Result | Units | Location type | Event | Method | Report | Versions |
|---|---|---|---|---|---|---|---|---|
| Jan 04, 2026 | Iron, Total | 0 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1364296 | |
| Jan 04, 2026 | Oil and Grease | 0 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1364296 | |
| Jan 04, 2026 | pH | 6.83 | SU | Effluent | Qualifying Storm Event | A4500HB | 1364296 | |
| Jan 04, 2026 | Total Suspended Solids (TSS) | 0 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1364296 | |
| Feb 13, 2025 | Iron, Total | .27 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1323861 | |
| Feb 13, 2025 | Oil and Grease | ND | mg/L | Effluent | Qualifying Storm Event | E1664A | 1323861 | |
| Feb 13, 2025 | pH | 8.3 | SU | Effluent | Qualifying Storm Event | A4500HB | 1323861 | |
| Feb 13, 2025 | Total Suspended Solids (TSS) | 37.2 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1323861 | |
| Jan 22, 2024 | Iron, Total | .33 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1277731 | |
| Jan 22, 2024 | Oil and Grease | 1 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1277731 | |
| Jan 22, 2024 | pH | 7.4 | SU | Effluent | Qualifying Storm Event | A4500HB | 1277731 | |
| Jan 22, 2024 | Total Suspended Solids (TSS) | 22 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1277731 | |
| Mar 29, 2023 | Iron, Total | .14 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1235070 | |
| Mar 29, 2023 | Oil and Grease | < 1 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1235070 | |
| Mar 29, 2023 | pH | 8.8 | SU | Effluent | Qualifying Storm Event | A4500HB | 1235070 | |
| Mar 29, 2023 | Total Suspended Solids (TSS) | 8 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1235070 | |
| Nov 08, 2022 | Iron, Total | .081 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1216162 | |
| Nov 08, 2022 | Oil and Grease | < 5 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1216162 | |
| Nov 08, 2022 | pH | 7.8 | SU | Effluent | Qualifying Storm Event | A4500HB | 1216162 | |
| Nov 08, 2022 | Total Suspended Solids (TSS) | < 10 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1216162 | |
| Jan 17, 2022 | Iron, Total | .19 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1178336 | |
| Jan 17, 2022 | Oil and Grease | < 5 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1178336 | |
| Jan 17, 2022 | pH | 6.6 | SU | Effluent | Qualifying Storm Event | A4500HB | 1178336 | |
| Jan 17, 2022 | Total Suspended Solids (TSS) | < 10 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1178336 | |
| Oct 25, 2021 | Iron, Total | .1 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1168627 | |
| Oct 25, 2021 | Oil and Grease | < 5 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1168627 | |
| Oct 25, 2021 | pH | 5.8 | SU | Effluent | Qualifying Storm Event | A4500HB | 1168627 | |
| Oct 25, 2021 | Total Suspended Solids (TSS) | < 10 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1168627 | |
| Dec 28, 2020 | Iron, Total | .05 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1139488 | |
| Dec 28, 2020 | Oil and Grease | < 5 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1139488 | |
| Dec 28, 2020 | pH | 8.5 | SU | Effluent | Qualifying Storm Event | A4500HB | 1139488 | |
| Dec 28, 2020 | Total Suspended Solids (TSS) | < 10 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1139488 | |
| May 18, 2020 | Iron, Total | 1 | mg/L | Effluent | Qualifying Storm Event | A3111B | 1109216 | |
| May 18, 2020 | Oil and Grease | < 5 | mg/L | Effluent | Qualifying Storm Event | A5220B | 1109216 | |
| May 18, 2020 | pH | 6.6 | SU | Effluent | Qualifying Storm Event | A4500HB | 1109216 | |
| May 18, 2020 | Total Suspended Solids (TSS) | 41 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1109216 | |
| Dec 04, 2019 | Iron, Total | .074 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1109216 | |
| Dec 04, 2019 | Oil and Grease | .5 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1109216 | |
| Dec 04, 2019 | pH | 7.6 | SU | Effluent | Qualifying Storm Event | A4500HB | 1109216 | |
| Dec 04, 2019 | Total Suspended Solids (TSS) | 9 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1109216 | |
| Dec 07, 2018 | Iron, Total | .19 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1125844 | |
| Dec 07, 2018 | Oil and Grease | 8 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1125844 | |
| Dec 07, 2018 | pH | 6.7 | SU | Effluent | Qualifying Storm Event | A4500HB | 1125844 | |
| Dec 07, 2018 | Total Suspended Solids (TSS) | 20 | mg/L | Effluent | Qualifying Storm Event | A2540D | 1125844 | |
| Jul 11, 2018 | Iron, Total | .093 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1125845 | |
| Jul 11, 2018 | Iron, Total | .28 | mg/L | Effluent | Qualifying Storm Event | E200.7 | 1125845 | |
| Jul 11, 2018 | Oil and Grease | 8 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1125845 | |
| Jul 11, 2018 | Oil and Grease | < 5 | mg/L | Effluent | Qualifying Storm Event | E1664A | 1125845 | |
| Jul 11, 2018 | pH | 6.3 | SU | Effluent | Qualifying Storm Event | A4500HB | 1125845 | |
| Jul 11, 2018 | pH | 7.6 | SU | Effluent | Qualifying Storm Event | A4500HB | 1125845 |
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 | 1 | 1 Violation · 0 Potential (preliminary) · 0 Dismissed | Aug 28, 2020 – Aug 28, 2020 | Oct 21, 2026 | All violations |
| Enforcement actions | 1 | 1 issued · 0 draft · 0 withdrawn, rescinded or superseded | Aug 28, 2020 – Aug 28, 2020 | Oct 21, 2026 | All actions |
| Inspections | 1 | inspections, not findings | Nov 12, 2025 – Nov 12, 2025 | Oct 21, 2026 | All inspections |
| Annual reports | 10 | certified reports (contents not shown) | 2016 – 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 (13 records, newest first)
| Date | Record | ID | Type or purpose | Status as published | Detail |
|---|---|---|---|---|---|
| Jul 06, 2026 | Annual reports | 1338904 | Annual report 2025 | — | |
| Nov 12, 2025 | Inspections | 2069519 | B Type compliance | Performed | No Further Action |
| Jul 15, 2025 | Annual reports | 1297928 | Annual report 2024 | — | |
| Jul 08, 2024 | Annual reports | 1247190 | Annual report 2023 | — | |
| Jul 12, 2022 | Annual reports | 1193381 | Annual report 2022 | — | |
| Jul 12, 2021 | Annual reports | 1117196 | Annual report 2021 | — | |
| Jan 21, 2021 | Annual reports | 1065402 | Annual report 2020 | — | |
| Aug 28, 2020 | Enforcement actions | 437297 | NOV (Notice of Violation) | Historical | |
| Aug 28, 2020 | Violations | 873748 | Late Report | Violation | Report |
| Jun 16, 2020 | Annual reports | 982491 | Annual report 2019 | — | |
| Jul 11, 2019 | Annual reports | 958834 | Annual report 2018 | — | |
| Aug 02, 2018 | Annual reports | 944271 | Annual report 2017 | — | |
| Jun 20, 2017 | Annual reports | 910256 | Annual report 2016 | — |
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.