California / Reports /

Sanitary sewer overflow (SSO) reported — San Dimas City, Sep 13, 2026

Ended (as reported) · California State Water Resources Control Board (CIWQS Sanitary Sewer System Database)

Source: California State Water Resources Control Board (CIWQS Sanitary Sewer System Database) via State Water Board CIWQS Sanitary Sewer System spill data: Cat1-2-3-Spills.txt (nightly flat file), record 908128, reported Sep 13, 2026, 6:11 PM PDT, retrieved 2026-11-05 15:08 UTC · Read the original notice

Read the original notice · Report an error

1. Reported wastewater outlet

Operator named in the record: San Dimas City (federal wastewater discharge permit, NPDES, 4SSO10425). Outlet: “2386-0218 ([house number removed] Eaton Road, San Dimas, CA 91773)”. Location: 34.10526, -117.83556; location source: given in the source record.

Outfall: a pipe or outlet where wastewater enters a water body.

2. Waters named in the notice

The notice names: “Walnut Creek and San Gabriel River”. DirtyWaterWatch links this report to Walnut Creek, CA. Match basis: the water named in the report.

3. Estimated downstream stretch

No downstream estimate is available for this report.

Open on the main map

When it happened and when it was reported

Event and notice times use Eastern Time (EST or EDT). Retrieval times use Coordinated Universal Time (UTC).

Started

Sep 13, 2026, 3:10 PM PDT

Ended

Sep 13, 2026, 5:00 PM PDT

Detail provided by the source

Times known to the minute

Reported to the source

Sep 13, 2026, 6:11 PM PDT

Published

not given

Source last updated

Sep 24, 2026, 12:00 AM PDT

Last retrieved by DirtyWaterWatch

2026-11-05 15:08 UTC

What and how much

Type

Sanitary sewer overflow (SSO): sewage spills from a sewer meant to carry sewage separately from rainwater.

Status in the record

Ended (as reported)

Material

“untreated sewage”

Volume

3,500 gallons (estimated)

Volume as reported

“3,500 gallons spilled (estimated total leaving the sewer system); 3,000 gallons reached surface water; 500 gallons recovered”

Advice from California State Water Resources Control Board (CIWQS Sanitary Sewer System Database)

This report includes no advice. Check current local health notices.

Advice period

This report does not state a period. See the rule DirtyWaterWatch applies and its source.

Basis

not stated

Status history from this report

• Discharge or advisory reported Walnut Creek: Discharge reported ongoing, Sep 13, 2026, 3:10 PM PDT to Sep 13, 2026, 5:00 PM PDT
• Caution Walnut Creek: Within the caution period after the reported end, Sep 13, 2026, 5:00 PM PDT to Sep 16, 2026, 5:00 PM PDT

Source: DirtyWaterWatch calculations using this report and the published status rules. Updated 2026-11-06 09:03 UTC.

Source and versions

Source

State Water Board CIWQS Sanitary Sewer System spill data: Cat1-2-3-Spills.txt (nightly flat file)

Source record number

908128

Original notice

Read the original notice

Earlier version

None: this is the first record

Later versions

None

{
  "region": "4",
  "wdid": "4SSO10425",
  "enrollee_status": "Active",
  "system_name": "San Dimas City CS",
  "agency_name": "San Dimas City",
  "spill_event_id": "908128",
  "version": "1.2",
  "spill_status": "Certified",
  "draft_submitted_on": "16-SEP-26",
  "first_certified_on": "24-SEP-26",
  "final_certified_on": "24-SEP-26",
  "spill_type": "Category 1 Spill",
  "location_name": "2386-0218 ([house number removed] Eaton Road, San Dimas, CA 91773)",
  "enrollee_notified_at": "09/13/2026 15:21",
  "crew_arrival_at": "09/13/2026 16:42",
  "start_at": "09/13/2026 15:10",
  "caloes_notified_at": "09/13/2026 18:11",
  "caloes_control_number": "26-4779",
  "technical_report_on": null,
  "lat": "34.10526",
  "lon": "-117.83556",
  "appearance_points": "Manhole",
  "volume_total_gal": "3500",
  "reached_drainage_system": "Y",
  "volume_recovered_from_drainage_gal": "0",
  "volume_left_in_drainage_gal": "3000",
  "volume_to_surface_water_gal": "3000",
  "volume_recovered_gal": "500",
  "destinations": "Drainage Conveyance System that discharges to surface water; Paved Surface; Street/Curb and Gutter (2 3)",
  "destination_points_given": "Y",
  "end_at": "09/13/2026 17:00",
  "causes": "Debris-General; Debris-wipes/Non-disposables",
  "failure_location": "Gravity Mainline",
  "storm_event": "N",
  "response_completed_at": "09/13/2026 17:38",
  "receiving_water": "Walnut Creek and San Gabriel River",
  "receiving_water_type": "River; Stream/Creek",
  "public_access_impact": "Other (specify below)",
  "closing_entity": "N/A",
  "days_closed_or_restricted": "0",
  "within_1000_ft_of_intake": "N",
  "samples_collected": "N",
  "spill_category": "1",
  "reached_water": true,
  "destination_points": [
    {
      "lat": 34.105,
      "lon": -117.836
    },
    {
      "lat": 34.105,
      "lon": -117.837
    }
  ]
}