Washington / Reports /

Sanitary sewer overflow (SSO) reported — Seattle CSO, Oct 21, 2026

Ended (as reported) · Washington State Department of Ecology (sewage spill list, RCW 90.48.636)

Source: Washington State Department of Ecology (sewage spill list, RCW 90.48.636) via Washington Ecology Sewage Spills list (RCW 90.48.636 public website), record 69067dd2-e5b5-4e8a-8412-ad704117ba2b, the source gives no report time, retrieved 2026-11-06 06:01 UTC · Read the original notice

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1. Reported wastewater outlet

Operator named in the record: Seattle CSO (federal wastewater discharge permit, NPDES, WA0031682). Outlet: “1100 Block of 23rd Ave S, Seattle”. Location: not given in the report or in the outlet records.

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

2. Waters named in the notice

The notice names: “Duwamish Waterway”. DirtyWaterWatch links this report to Duwamish Waterway, WA. Match basis: the water named in the report.

3. Estimated downstream stretch

No downstream estimate is available for this report.

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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

Oct 21, 2026, 8:41 PM EDT

Ended

Oct 21, 2026, 9:18 PM EDT

Detail provided by the source

Times known to the minute

Reported to the source

not given

Published

not given

Source last updated

not given

Last retrieved by DirtyWaterWatch

2026-11-06 06:01 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

“None (Raw Sewage)”

Volume

15 gallons (not stated whether estimated or measured)

Volume as reported

“15 Gallons”

Advice from Washington State Department of Ecology (sewage spill list, RCW 90.48.636)

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 Duwamish Waterway: Discharge reported ongoing, Oct 21, 2026, 8:41 PM EDT to Oct 21, 2026, 9:18 PM EDT
• Caution Duwamish Waterway: Within the caution period after the reported end, Oct 21, 2026, 9:18 PM EDT to Oct 24, 2026, 9:18 PM EDT

Source: DirtyWaterWatch calculations using this report and the published status rules. Updated 2026-11-06 06:13 UTC.

Source and versions

Source

Washington Ecology Sewage Spills list (RCW 90.48.636 public website)

Source record number

69067dd2-e5b5-4e8a-8412-ad704117ba2b

Original notice

Read the original notice

Earlier version

None: this is the first record

Later versions

None

{
  "row": {
    "objectid": 94,
    "globalid": "{69067DD2-E5B5-4E8A-8412-AD704117BA2B}",
    "ecology_region": "Northwest",
    "start_date_and_time": 1792629660000,
    "permitee": "Seattle CSO",
    "location": "1100 Block of 23rd Ave S, Seattle",
    "county": "King",
    "initial_estimated_amount": "Unknown/Not Reported",
    "level_of_treatment": "None (Raw Sewage)",
    "potentially_impacted_area": "MS4 catch basin and the Duwamish Waterway",
    "end_event_timedate": 1792631880000,
    "final_event_duration_hours": "0.62 Hours",
    "final_total_event_volume": "15 Gallons",
    "link_to_5_day_report": "https://apps.ecology.wa.gov/paris/DownloadDocument.aspx?id=654058",
    "event_type": "Sanitary Sewer Overflow_",
    "event_type_other": null,
    "erts_number": "751040",
    "was_the_spill_continuous": "Continuous"
  },
  "potentially_impacted_area": "MS4 catch basin and the Duwamish Waterway",
  "reached_water": true,
  "report_url": "https://apps.ecology.wa.gov/paris/DownloadDocument.aspx?id=654058",
  "erts_number": "751040",
  "county": "King",
  "duration_text": "0.62 Hours",
  "continuous": "Continuous"
}