Sewerage Agency Southern Marin

Active WDID 2 21I000240 Mill Valley, Marin County Region 2 · San Francisco Bay

At a glance

Permit Evidence: SMARTS record
Active Industrial
Notice of Intent (WDID code I) · Permits and applications
Location Evidence: facility-reported
Mill Valley, Marin County
Region 2 · San Francisco Bay · Location · Statewide map
Receiving water
Richardson Bay (as reported by the facility)
Evidence: identification corroborated Richardson Bay Details
Identified receiving water on the 2026 303(d) list
Yes · 10 Appendix A decisions, category 5 Evidence: State-published
Describes the waterbody, not this facility · Waterbody profile
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
253 distinct results, 11 reporting years (2015 to 2025)
Most recent sample Apr 20, 2026 · Monitoring
Compliance and enforcement records Evidence: SMARTS record
2 inspections · 1 violation record · 1 enforcement action
Counts as published in SMARTS; not a compliance determination · Details
SMARTS TMDL records Evidence: SMARTS-reported
0 records
TMDL records

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

Open this facility on the statewide map

Reported location Evidence: facility-reported

Coordinates
37.89657, -122.52813
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
450 Sycamore Ave, Mill Valley 94941
Regional Water Board
2 — San Francisco Bay

HUC12 watershed Evidence: spatial

  • Angel Island-Frontal San Francisco Bay Estuaries HUC12 180500021001

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
SEWERAGE AGENCY OF SOUTHERN MARIN
Primary industry (SIC)
4952-Sewerage Systems
Application ID
182125
NOI processed
Mar 06, 1992
Last certified
Feb 28, 2025
Facility size
5 Acres

Retrieved from SMARTS Oct 20, 2026. Verify against SMARTS before relying on it.

Permit history

Storm water applications for this WDID, newest first
ApplicationTypeStatusProcessedTerminatedCertified
182125 IndustrialActiveMar 06, 1992 —Feb 28, 2025

Every storm water application SMARTS records for this WDID, newest first (1).

Receiving water

Reported by the facility Evidence: facility-reported
Richardson Bay
Discharges directly / indirectly
Y / N (as answered in the permit application)

Evidence: identification corroborated Richardson Bay CAB2031201019980929120559

Receiving water reported by facility — waterbody identification corroborated by geographic evidence.

Nearest distance from the reported facility location: 1.5 km. Method receiving_water/2.

2026 Integrated Report status Evidence: State-published

Richardson Bay is on the 2026 Clean Water Act section 303(d) list (10 Appendix A decisions; category 5).

2026 Appendix A decisions for the identified receiving water
PollutantCategoryListing decisionTMDL requirementDecision ID
Chlordane5Do Not Delist from 303(d) list (TMDL required list) 5A151203
DDT (Dichlorodiphenyltrichloroethane)5Do Not Delist from 303(d) list (TMDL required list) 5A151529
Dieldrin5Do Not Delist from 303(d) list (TMDL required list) 5A140814
Dioxin compounds (including 2,3,7,8-TCDD)5Do Not Delist from 303(d) list (TMDL required list) 5A151204
Furan Compounds5Do Not Delist from 303(d) list (TMDL required list) 5A151206
Indicator Bacteria5Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL) 5B · Richardson Bay Pathogens148680
Invasive Species5Do Not Delist from 303(d) list (TMDL required list) 5A170589
Mercury5Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL) 5B · San Francisco Bay Mercury145497
PCBs (Polychlorinated biphenyls)5Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL) 5B · San Francisco Bay PCBs140819
PCBs (Polychlorinated biphenyls) (dioxin-like)5List on 303(d) list (being addressed by USEPA approved TMDL) 5B · San Francisco Bay PCBs69186

Published by the State Water Resources Control Board (2026 California Integrated Report, Appendix A). Listing status is taken from Appendix A only. State Board adoption 2026-02-03; USEPA approval not confirmed. A listing describes the waterbody, not this facility. Waterbody profile.

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.

Nearest 2026 Integrated Report waterbodies
Waterbody (2026 Integrated Report)Distance2026 303(d) listAppendix A decisions
Arroyo Corte Madera Del Presidio CAR2032002020000413134900172 m listed1

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.

253 distinct measurements across 4 parameters, most recent sample Apr 20, 2026.

By reporting year

Distinct results by reporting year
Reporting year (July–June)Distinct resultsParametersWith several versionsFirst sampleLast sample
2025243 0 Oct 13, 2025Apr 20, 2026
2024123 0 Nov 11, 2024Mar 12, 2025
2023123 0 Dec 18, 2023Feb 29, 2024
2022123 0 Dec 01, 2022Feb 27, 2023
2021123 0 Oct 21, 2021Apr 14, 2022
2020183 0 Nov 13, 2020Jan 04, 2021
2019303 0 Dec 11, 2019May 11, 2020
2018363 0 Oct 02, 2018Mar 05, 2019
2017213 0 Nov 10, 2017Jan 18, 2018
2016284 0 Oct 14, 2016Feb 02, 2017
2015484 0 Sep 14, 2015Apr 22, 2016

By parameter

Distinct results by parameter
ParameterUnitsMeasurementsBelow detectionFirst sampleLast sampleResults
Oil and Greasemg/L79 70Sep 14, 2015Apr 20, 2026 Results
pHSU79 0Sep 14, 2015Apr 20, 2026 Results
Total Suspended Solids (TSS)mg/L79 1Sep 14, 2015Apr 20, 2026 Results
Electrical Conductivity @ 25 Deg. Cumhos/cm16 0Sep 14, 2015Oct 25, 2016 Results

All results (253 distinct rows)

Reported monitoring results, newest first
Sample dateParameterResultUnitsLocation typeEventMethodReportVersions
Apr 20, 2026 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1372781
Apr 20, 2026 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1372781
Apr 20, 2026 pH 6.5 SU Effluent Qualifying Storm Event A4500HB 1372781
Apr 20, 2026 pH 6.36 SU Effluent Qualifying Storm Event A4500HB 1372781
Apr 20, 2026 Total Suspended Solids (TSS) 21 mg/L Effluent Qualifying Storm Event A2540D 1372781
Apr 20, 2026 Total Suspended Solids (TSS) 19.7 mg/L Effluent Qualifying Storm Event A2540D 1372781
Apr 10, 2026 Oil and Grease DNQ 1.8 mg/L Effluent Qualifying Storm Event E1664A 1372739
Apr 10, 2026 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1372739
Apr 10, 2026 pH 6.92 SU Effluent Qualifying Storm Event A4500HB 1372739
Apr 10, 2026 pH 6.32 SU Effluent Qualifying Storm Event A4500HB 1372739
Apr 10, 2026 Total Suspended Solids (TSS) 44.3 mg/L Effluent Qualifying Storm Event A2540D 1372739
Apr 10, 2026 Total Suspended Solids (TSS) 28.7 mg/L Effluent Qualifying Storm Event A2540D 1372739
Mar 31, 2026 Oil and Grease DNQ 2.2 mg/L Effluent Qualifying Storm Event E1664A 1372736
Mar 31, 2026 pH 6.37 SU Effluent Qualifying Storm Event A4500HB 1372736
Mar 31, 2026 Total Suspended Solids (TSS) 64.8 mg/L Effluent Qualifying Storm Event A2540D 1372736
Nov 13, 2025 Oil and Grease DNQ 2.2 mg/L Effluent Qualifying Storm Event E1664A 1361091
Nov 13, 2025 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1361091
Nov 13, 2025 pH 7.26 SU Effluent Qualifying Storm Event A4500HB 1361091
Nov 13, 2025 pH 7.35 SU Effluent Qualifying Storm Event A4500HB 1361091
Nov 13, 2025 Total Suspended Solids (TSS) 81.5 mg/L Effluent Qualifying Storm Event A2540D 1361091
Nov 13, 2025 Total Suspended Solids (TSS) 43.8 mg/L Effluent Qualifying Storm Event A2540D 1361091
Oct 13, 2025 Oil and Grease DNQ 4.1 mg/L Effluent Qualifying Storm Event E1664A 1355450
Oct 13, 2025 pH 6.31 SU Effluent Qualifying Storm Event A4500HB 1355450
Oct 13, 2025 Total Suspended Solids (TSS) 28.4 mg/L Effluent Qualifying Storm Event A2540D 1355450
Mar 12, 2025 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1325123
Mar 12, 2025 pH 6.74 SU Effluent Qualifying Storm Event A4500HB 1325123
Mar 12, 2025 Total Suspended Solids (TSS) 5.2 mg/L Effluent Qualifying Storm Event A2540D 1325123
Jan 31, 2025 Oil and Grease DNQ 1.6 mg/L Effluent Qualifying Storm Event E1664A 1319874
Jan 31, 2025 pH 6.98 SU Effluent Qualifying Storm Event A4500HB 1319874
Jan 31, 2025 Total Suspended Solids (TSS) 6.3 mg/L Effluent Qualifying Storm Event A2540D 1319874
Nov 20, 2024 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1316625
Nov 20, 2024 pH 7.09 SU Effluent Qualifying Storm Event A4500HB 1316625
Nov 20, 2024 Total Suspended Solids (TSS) 10.5 mg/L Effluent Qualifying Storm Event A2540D 1316625
Nov 11, 2024 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1316620
Nov 11, 2024 pH 7.02 SU Effluent Qualifying Storm Event A4500HB 1316620
Nov 11, 2024 Total Suspended Solids (TSS) 13 mg/L Effluent Qualifying Storm Event A2540D 1316620
Feb 29, 2024 Oil and Grease DNQ 1.5 mg/L Effluent Qualifying Storm Event E1664A 1282001
Feb 29, 2024 pH 7.43 SU Effluent Qualifying Storm Event A4500HB 1282001
Feb 29, 2024 Total Suspended Solids (TSS) 17.5 mg/L Effluent Qualifying Storm Event A2540D 1282001
Jan 31, 2024 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1281995
Jan 31, 2024 pH 7.76 SU Effluent Qualifying Storm Event A4500HB 1281995
Jan 31, 2024 Total Suspended Solids (TSS) 16.28 mg/L Effluent Qualifying Storm Event A2540D 1281995
Jan 09, 2024 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1274429
Jan 09, 2024 pH 7.63 SU Effluent Qualifying Storm Event A4500HB 1274429
Jan 09, 2024 Total Suspended Solids (TSS) 6.5 mg/L Effluent Qualifying Storm Event A2540D 1274429
Dec 18, 2023 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1274393
Dec 18, 2023 pH 7.35 SU Effluent Qualifying Storm Event A4500HB 1274393
Dec 18, 2023 Total Suspended Solids (TSS) 15.4 mg/L Effluent Qualifying Storm Event A2540D 1274393
Feb 27, 2023 Oil and Grease ND mg/L Effluent Qualifying Storm Event E1664A 1232110
Feb 27, 2023 pH 6.71 SU Effluent Qualifying Storm Event A4500HB 1232110

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.

Compliance and enforcement records by type
Record typeRecordsAs publishedDatesRetrievedList
Violations1 0 Violation · 0 Potential (preliminary) · 1 Dismissed Jul 04, 2005 – Jul 04, 2005 Oct 21, 2026 All violations
Enforcement actions1 1 issued · 0 draft · 0 withdrawn, rescinded or superseded Aug 05, 2005 – Aug 05, 2005 Oct 21, 2026 All actions
Inspections2inspections, not findings Feb 19, 2004 – Mar 17, 2004 Oct 21, 2026 All inspections
Annual reports11certified reports (contents not shown) 2015 – 2025 Oct 21, 2026 All reports
Water-quality-based corrective action reports0reports, 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 (15 records, newest first)
Compliance and enforcement records, newest first
DateRecordIDType or purposeStatus as publishedDetail
Jul 14, 2026 Annual reports 1336633 Annual report 2025 —
Jul 10, 2025 Annual reports 1295502 Annual report 2024 —
Jul 11, 2024 Annual reports 1244652 Annual report 2023 —
Jul 14, 2023 Annual reports 1190721 Annual report 2022 —
Jul 15, 2022 Annual reports 1114219 Annual report 2021 —
Jul 20, 2021 Annual reports 1070296 Annual report 2020 —
Jun 30, 2020 Annual reports 987675 Annual report 2019 —
Jul 12, 2019 Annual reports 955293 Annual report 2018 —
Jul 13, 2018 Annual reports 940713 Annual report 2017 —
Jul 06, 2017 Annual reports 880058 Annual report 2016 —
Jul 18, 2016 Annual reports 845680 Annual report 2015 —
Aug 05, 2005 Enforcement actions 310576 NNC (Notice of Non-Compliance) Historical97-03DWQ
Jul 04, 2005 Violations 434537 Late Report DismissedReport
Mar 17, 2004 Inspections 335568 Inspection from Vehicle —
Feb 19, 2004 Inspections 335552 Inspection from Vehicle —

Sources and provenance

Sources behind this page
InformationSourceRetrieved or published
Permit, location, receiving-water textSMARTS Industrial Application Specific DataOct 20, 2026
Permit historySMARTS Storm Water ApplicationsOct 20, 2026
Monitoring resultsSMARTS Industrial Parameter DataOct 20, 2026
Watershed Boundary Dataset HU2 GeoPackages 15, 16, 18 (WBDHU12)USGS2026-10-22
2026 California Integrated Report, Appendix A: 2026 303(d) List (final)SWRCB2026-10-22
Final_2026_Rivers_and_Streams + Final_2026_Lakes_and_Reservoirs (FeatureServer 0)SWRCB GIS2026-10-22
SMARTS TMDL requirementsSMARTS2026-10-21

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

Records are shown as published and are not compliance determinations. How geographic context is derived.