Combined sewer overflow (CSO) reported — Seattle Public Utilities

Ended (as reported) · King County Wastewater Treatment Division and Seattle Public Utilities (CSO status map)

Source: King County Wastewater Treatment Division and Seattle Public Utilities (CSO status map) via King County / Seattle CSO overflow status CSV, record npdes145-20261105T1310, reported Nov 5, 2026, 4:10 PM EST, retrieved 2026-11-05 21:17 UTC · Read the original notice

Current status from this report

Discharge or advisory reported on Lake Union: Post-discharge period applies. Current rule period ends Nov 7, 2026, 4:10 PM EST. This is not a water-quality test.

Why this status: Discharge or advisory reported: Washington post-discharge period.

Why we use this rule: Washington law sets no period after a sewage spill during which the water is to be avoided. The Department of Ecology must post on a public website each sewage spill reported to it under an individual water quality permit, with the estimated volume, the level of treatment, when it began, where, when it ended once known and the area potentially affected, and add the final information within a reasonable time after the spill ends (RCW 90.48.636); the law sets no posting deadline, and Ecology aims to post within five working days of the operator's report. Operators report spills to Ecology under their permits. King County and Seattle advise staying out of the water near a combined sewer outfall for 48 hours after it overflows; that window is used for the overflows their status map reports. This site marks a reported discharge while it runs and applies its own caution after it ends

Source: RCW 90.48.632 and 90.48.636 (2025 c 315); Washington State Department of Ecology, Sewage spills; King County CSO status map. This rule on the methods page, with its source

A report is not a test of the water. See how we assign statuses.

Read the original notice · Report an error

1. Reported wastewater outlet

Operator named in the record: Seattle Public Utilities (federal wastewater discharge permit, NPDES, WA0031682). Outlet: 145 “Seattle CSO outfall 145”. Location: 47.65004, -122.33061; location source: given in the source record.

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

Source: EPA ECHO wastewater outlet records, permit WA0031682, outlet 145. Location linked by DirtyWaterWatch.

2. Waters named in the notice

The notice names no water. DirtyWaterWatch links this report to Lake Union, WA. Match basis: the outlet's permit and number in EPA and state records.

3. Estimated downstream stretch

We estimate routes only on rivers before they become tidal. We do not estimate routes through tidal water or lakes.

Map sources: water outlines and launches from OpenBoatLaunch and OpenStreetMap contributors (Open Database License); wastewater outlets from EPA and state records; downstream estimates by DirtyWaterWatch using U.S. Geological Survey maps and flow data. Base map: OpenFreeMap and OpenMapTiles.

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: not reported
Ended: Nov 5, 2026, 4:10 PM EST
Detail provided by the source: Times known poll
Reported to the source: Nov 5, 2026, 4:10 PM EST
Published: not given
Source last updated: Nov 5, 2026, 4:10 PM EST
Last retrieved by DirtyWaterWatch: 2026-11-05 21:17 UTC

What and how much

Type: Combined sewer overflow (CSO): sewage mixed with rainwater spills from a shared sewer system.
Status in the record: Ended (as reported)
Material: not stated
Volume: volume not reported (not stated whether estimated or measured)
Volume as reported: none

Advice from King County Wastewater Treatment Division and Seattle Public Utilities (CSO status map)

“Stay out of the water near combined sewer overflow outfalls for 48 hours after a combined sewer overflow occurs.”
King County Wastewater Treatment Division and Seattle Public Utilities (CSO status map) · King County's CSO status map: stay out of the water near the outfall for 48 hours after an overflow

Advice period: 48 hours
Basis: King County's CSO status map: stay out of the water near the outfall for 48 hours after an overflow

Status history from this report

Discharge or advisory reported Lake Union: Discharge reported ongoing, Nov 5, 2026, 4:10 PM EST to Nov 5, 2026, 4:10 PM EST
Discharge or advisory reported Lake Union: Post-discharge period applies, Nov 5, 2026, 4:10 PM EST to Nov 7, 2026, 4:10 PM EST (the end is scheduled: a new report can change it)
Caution Lake Union: Within the caution period after the reported end, Nov 7, 2026, 4:10 PM EST to Nov 9, 2026, 4:10 PM EST (scheduled: a new report can change it)

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

Source and versions

Source: King County / Seattle CSO overflow status CSV
Source record number: npdes145-20261105T1310
Original notice: Read the original notice
Earlier version: None: this is the first record
Later versions: None

Record details

Record details
Record identifier	wa-kc-cso-status-csv:npdes145-20261105T1310
Source identifier	wa-kc-cso-status-csv
Source record number	npdes145-20261105T1310
Earlier version	Not provided
Type	Combined sewer overflow (CSO)
Status in the report	Ended (as reported)
Sewer operator identifier	wa-seattle-spu
Sewer operator	Seattle Public Utilities
Federal wastewater discharge permit (NPDES)	WA0031682
Outlet number	145
Outlet name	Seattle CSO outfall 145
Water named in the report	Not provided
Linked waters	lake-union-wa
How this report was linked to the water	the outlet's permit and number in EPA and state records
Latitude	47.65
Longitude	-122.331
Location source	given in the source record
Location accuracy, in metres	Not provided
Started	Not provided
Ended	Nov 5, 2026, 4:10 PM EST (2026-11-05T13:10:00-08:00)
Detail provided by the source	poll
Reported to the source	Nov 5, 2026, 4:10 PM EST (2026-11-05T13:10:00-08:00)
Published	Not provided
Source last updated	Nov 5, 2026, 4:10 PM EST (2026-11-05T13:10:00-08:00)
Last retrieved by DirtyWaterWatch	Nov 5, 2026, 4:17 PM EST (2026-11-05T21:17:30Z)
Material	Not provided
Volume, in gallons	Not provided
Volume as reported	Not provided
How volume was determined	not stated whether estimated or measured
Authority	King County Wastewater Treatment Division and Seattle Public Utilities (CSO status map)
Advice	Quoted in full above
Advice period, in hours	48
Basis of the advice period	King County's CSO status map: stay out of the water near the outfall for 48 hours after an overflow
Original notice	https://kingcounty.gov/en/dept/dnrp/waste-services/wastewater-treatment/sewer-system-services/cso-status

Original source data

{
  "row": {
    "CSO_TagName": "NPDES145",
    "X_COORD": "-122.3306138",
    "Y_COORD": "47.65004146",
    "Name": "Seattle CSO",
    "DSN": "145",
    "DateTime": "11/05/2026 22:00",
    "Status": "OverflowLast48hrs"
  },
  "transitions": [
    {
      "fetched_at": "2026-11-05T21:17:30Z",
      "poll_time": "2026-11-05T13:10:00-08:00",
      "message": "OverflowLast48hrs"
    }
  ],
  "time_basis": {
    "precision": "poll: started_at and ended_at are the source's poll times of the snapshots our fetch saw, not the event's own start and end",
    "started_at": "the poll time of the first snapshot that said the unit was active; it began at or before then, after started_after when that is given",
    "ended_at": "the poll time of the first snapshot that no longer said active; it ended at or before then, after ended_after"
  },
  "started_after": null,
  "occurred_after": "2026-11-05T08:30:00-08:00",
  "start_basis": "first seen as recent: it began and ended between our polls; the start was not observed",
  "last_active_at": null,
  "ended_after": null,
  "end_basis": "poll",
  "closed_by": null,
  "resumed": null,
  "no_data_since": null,
  "vanished": null
}

Staff names, email addresses and phone numbers are removed from source data before it is stored.