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Washington / Sewer operators /

King County Wastewater Treatment Division (West Point, South, Brightwater, Vashon and Carnation plants and King County's CSOs)

Sewer utility with combined sewers · Washington · Seattle

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.

Solid dots mark combined sewer outfalls. Ringed dots mark treatment plant outfalls. Small hollow diamonds mark places named in its overflow reports (provisional). Grey dots are closed outfalls. A yellow ring with a dashed edge means discharge likely or possible: heavy rain, no report received. Dashed river stretches are estimates of where a discharge travels. Square boat markers mark boat launches listed by OpenBoatLaunch.

Federal wastewater discharge permit (NPDES)
WA0029181, WA0029581, WA0032247, WA0022527, WA0032182, WAR002511, WAR125522
Wastewater outlets
48 combined sewer outfalls and 18 treatment plant outfalls listed by EPA or state agencies; 1 place named in its own overflow reports (provisional locations) (the state's combined sewer records list 66) · List
Waters listed as receiving wastewater
Puget Sound; Elliott Bay; Duwamish River; Lake Washington; Lake Union / Ship Canal
Tracked waters
Bear Creek, WA, Black River, WA, Duwamish River, WA, Duwamish Waterway, WA, East Passage, WA, East Waterway, WA, Elliott Bay, WA, Harbor Island Reach, WA, Howell Creek, WA, Lake Union, WA, Lake Washington Ship Canal, WA, Lake Washington, WA, Montlake Cut, WA, Portage Bay, WA, Puget Sound, WA, Salmon Bay Waterway, WA, Snoqualmie River, WA
Discharge records counted
2 records · latest
Total reported volume in these records
85,000 gallons across the 1 record that give a volume (1 without one)

These totals reflect the records we track. Missing volumes and gaps in reporting limit comparisons between operators.

Sources: EPA ECHO and the operator and state sources linked below. Counts use the discharge records on this page. Updated 2026-11-06 06:13 UTC.

Public notices and alerts

Pages where King County Wastewater Treatment Division (West Point, South, Brightwater, Vashon and Carnation plants and King County's CSOs) or the state publishes its notices (check them for an alert sign-up):

Its public-notice channels

Source: King County Wastewater Treatment Division (West Point, South, Brightwater, Vashon and Carnation plants and King County's CSOs)'s public notice and alert pages and the state's notification records; DirtyWaterWatch register of public-notice channels and its page monitor.

Report a missing notice or error

Rain and discharges

The NOAA MRMS radar-only rainfall estimate for the 24 hours to the latest hour, read every hour at each outfall from the radar grid. We show a caution when the rain reaches the amount below and no discharge report has arrived.

Threshold
0.1 in of rain in 24 hours (site default: This site's default: 0.1 inch of rain in 24 hours at a combined sewer outfall, applied where the state publishes no rain trigger of its own)
Radar now
1.4 in in the 24 hours to Nov 6, 2026, 12:00 AM EST
Forecast
Rain expected: 0.16 in forecast in the next 24 hours (NWS forecast issued Nov 5, 2026, 1:26 PM EST); discharges here have begun at 0.1 in.
Status
Discharge possible: heavy rain, no report received

Source: NOAA National Weather Service, MRMS radar-only rainfall estimate, valid Nov 6, 2026, 12:00 AM EST, retrieved 2026-11-06 06:09 UTC; threshold: site default; rule: How it works, discharge likely or possible.

Wastewater outlets

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

48 combined sewer outfalls and 18 treatment plant outfalls listed by EPA or state agencies; 1 place named in its own overflow reports (provisional locations). Discharge likely or possible now at some of them: see Rain and discharges above.

Combined sewer outfalls

48 outfalls · 8 closed · discharge possible now at 40

Discharge possible: heavy rain, no report received at 40 outfalls now: radar rainfall has reached the operator's threshold and no discharge report has arrived (NOAA radar estimate).

Showing 12 of 48.

Source: U.S. Environmental Protection Agency (EPA) national combined sewer outfall inventory (ECHO) and state outfall layers. Open or closed as EPA's inventory lists it. DirtyWaterWatch links outlets to waters using permit numbers, locations and names.

Treatment plant outfalls

18 outfalls

Showing 12 of 18.

Source: U.S. Environmental Protection Agency (EPA) permit records (ICIS-NPDES permitted features): where a treatment plant’s permitted discharge leaves. No national source says whether a plant outfall is open or closed.

Places named in overflow reports (provisional)

1 place

Provisional location from overflow reports. Where the operator's own reports put an overflow: a manhole, pump station or plant. Not an outfall listed in a permit.

  • Reported place · 1 overflow report, latest Jul 13, 2026 · confidence medium · no water record yet

Source: the operator's own overflow reports to the state. DirtyWaterWatch groups reports within 50 metres into one place and finds the water below it with U.S. Geological Survey river maps (NLDI, NHDPlus). Not a permitted outfall; provisional until an official outfall record exists.

Reports and advisories

Sanitary sewer overflow (SSO): sewage spills from a sewer meant to carry sewage separately from rainwater. Combined sewer overflow (CSO): sewage mixed with rainwater spills from a shared sewer system.

Reports linked to King County Wastewater Treatment Division (West Point, South, Brightwater, Vashon and Carnation plants and King County's CSOs), newest first
WhenReportStatus
to 1:32 PMPuget Sound · 103rd Ave SW at Vashon Highway, Vashon · SSO · “< 2,500 Gallons” report · notice · mapended
to 2:15 PMPuget Sound · 3380 Beach Drive SW, Seattle · CSO · 85,000 gallons report · notice · mapended

Sources: Washington Ecology Sewage Spills list (RCW 90.48.636 public website), retrieved 2026-11-06 06:01 UTC. A report's record id and times show when you hover or focus its "report" link.

Download these reports as CSV

All reports in Washington by year: 2026 (2 from King County Wastewater Treatment Division (West Point, South, Brightwater, Vashon and Carnation plants and King County's CSOs))

Other sewer operators on these waters

The last 90 days

Last 90 days, hour by hour. Red: discharge or advisory reported. Amber: caution. Hatched amber: end not confirmed. Plum: algal bloom advisory. Red or amber with a light line inside: beach advisory or caution. Dotted: monthly report (days with discharge, dates not given). Grey: no current status on the water outline. Purple hatching: a status resting on a source that could not be checked on schedule.
  • Caution: to
    1 report: Puget Sound 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Puget Sound 1
    Show records

    The records are also in the report table on this page.

Source: DirtyWaterWatch calculations using the reports named above and the published status rules. Updated 2026-11-06 06:13 UTC.

Reported discharges over time

  • Discharges reported by King County Wastewater Treatment Division (West Point, South, Brightwater, Vashon and Carnation plants and King County's CSOs), last 12 months2December 2025 to November 2026Verified reports where available, else notices; revisions and duplicates counted once.
  • Days with a discharge reported by King County Wastewater Treatment Division (West Point, South, Brightwater, Vashon and Carnation plants and King County's CSOs), last 12 months2December 2025 to November 2026A day counts once however many discharges were under way on it.
  • Hours with a discharge or advisory status from King County Wastewater Treatment Division (West Point, South, Brightwater, Vashon and Carnation plants and King County's CSOs)'s reports, last 12 months0December 2025 to November 2026Red hours by the map's rules: each discharge to its reported end plus the state's post-discharge period; overlapping hours count once.
  • 2026 season with a discharge or advisory status (King County Wastewater Treatment Division (West Point, South, Brightwater, Vashon and Carnation plants and King County's CSOs))0.0%May to October 2026; incomplete source coverageShare of May 1 to October 31 hours with red status by the map's rules, of the hours a source covered.

Treatment bypass: wastewater skips one or more treatment steps. Blended discharge: wastewater that skipped some treatment is mixed with treated wastewater.

Reported discharges per month

2 reported discharges, January 2022 to November 2026.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Treatment bypass, blended or other
  • No tracked source for this period
  • Incomplete source coverage
No tracked source

No tracked source covers January 2022 to May 2026.

Source: wa-ecology-sewage-spills. Records cover June 15, 2026 to November 6, 2026.

Show table

Hours with a discharge or advisory status per month

Hours when a water had a discharge or advisory status from this sewer operator's reports, under DirtyWaterWatch rules.

  • Discharge or advisory reported
  • No tracked source for this period
  • Incomplete source coverage
No tracked source

No tracked source covers January 2022 to May 2026. Official beach and cyanobacteria (harmful blue-green algae) advisories are counted on water pages only.

Source: wa-ecology-sewage-spills. Records cover June 15, 2026 to November 6, 2026.

Show table

Days with a reported discharge per month

A day counts when any counted discharge was under way on it, from its start to its reported end in Eastern Time; a report with no end counts its start day.

  • No tracked source for this period
  • Incomplete source coverage
No tracked source

No tracked source covers January 2022 to May 2026.

Source: wa-ecology-sewage-spills. Records cover June 15, 2026 to November 6, 2026.

Show table

Reported volume per year

Gallons (axis: K thousand, M million), summed from the 1 report that gave a volume as a number (1 did not).

  • Incomplete source coverage
Limited records

1 of 2 discharge reports gave no volume as a number; only numbers are summed.

Source: wa-ecology-sewage-spills. Records cover June 15, 2026 to November 6, 2026.

Show table

Hours with a discharge or advisory status per year

Hours with a discharge or advisory status each year under DirtyWaterWatch rules; 2026 to date.

  • Discharge or advisory reported
  • Incomplete source coverage
Limited records

Official beach and cyanobacteria (harmful blue-green algae) advisories are counted on water pages only.

Source: wa-ecology-sewage-spills. Records cover June 15, 2026 to November 6, 2026.

Show table

Share of the May to October season with a discharge or advisory status

Share of the hours from May 1 to October 31 with a discharge or advisory status under DirtyWaterWatch rules.

  • Discharge or advisory reported
  • Season with incomplete source coverage

Seasons with incomplete source coverage: 2026. The share is of the hours a source covered. Official beach and cyanobacteria (harmful blue-green algae) advisories are counted on water pages only.

Source: wa-ecology-sewage-spills. Records cover June 15, 2026 to November 6, 2026.

Show table

Reported discharges by calendar month, all years

Every counted discharge report, by the calendar month it began.

Months are summed over every year a tracked source covers; the table gives the number of years behind each month.

Source: wa-ecology-sewage-spills. Records cover June 15, 2026 to November 6, 2026.

Show table

Reported discharges by wastewater outlet

Wastewater outlets with the most tracked discharge records: 2 of 2, all years. Counts depend on reporting coverage and do not measure legal compliance or harm.

Source: wa-ecology-sewage-spills. Records cover June 15, 2026 to November 6, 2026.

Show table
How these charts are counted

We count each discharge once. Where a source publishes notices and confirmed reports, we use confirmed reports for an operator's month when available; otherwise we use notices. We combine revisions and exclude duplicate state reports copied by the U.S. Environmental Protection Agency (EPA). Monthly and yearly totals appear separately. Status hours follow this site's rules. Shaded gaps mean missing coverage, not zero discharges.

  • wa-ecology-sewage-spills: records from June 15, 2026 to the latest update