Massachusetts / Events /

Combined sewer overflow: CITY OF CHELSEA, Oct 11, 2026

Ended (as reported) · CITY OF CHELSEA (MassDEP sewage notification portal)

Source: CITY OF CHELSEA (MassDEP sewage notification portal) via MassDEP CSO API behind the portal (eeaonline.eea.state.ma.us/dep/CSOAPI/api/), record 313944f6-9ad0-4551-9d05-1537eda60be6, published Oct 20, 2026, 6:34 PM EDT, retrieved 2026-11-02 11:54 UTC · notice

1. The reported outfall

Outfall reported by CITY OF CHELSEA (MA0101877 outfall CHE008): “NORTHERN EDGE OF GULF BULK OIL STORAGE”. Location: 42.39471, -71.01915, from the state's or EPA's outfall layer.

2. Waters named in the notice

The notice names: “CHELSEA RIVER”. Not placed on a tracked water.

3. Modeled downstream reach

Not modeled: the reach model runs on rivers above the head of tide only.

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When: three different times

The time of the event, the time the source reported, published or updated it, and the time we fetched it are kept apart. Times are shown in New England time; the record keeps the original offsets.

Started

Oct 11, 2026, 8:00 PM EDT

Ended

Oct 11, 2026, 8:10 PM EDT

Precision

Known to the minute

Reported to the source

not given

Published

Oct 20, 2026, 6:34 PM EDT

Source last updated

not given

We fetched it

2026-11-02 11:54 UTC

What and how much

Type

Combined sewer overflow

Status in the record

Ended (as reported)

Material

“CSO – UnTreated”

Volume

not reported (not stated whether estimated or measured)

Volume in the source's words

none

Advice

“Avoid contact with these water bodies for 48 hours after the discharge or overflow ceases due to increased health risks from bacteria and other pollutants. See website for more information on whether specific resource areas, such as bathing beaches, are affected.”

Advice window

48 hours

Basis

314 CMR 16.04(10)(g)

Source and revisions

Source

MassDEP CSO API behind the portal (eeaonline.eea.state.ma.us/dep/CSOAPI/api/)

Record id at the source

313944f6-9ad0-4551-9d05-1537eda60be6

Original notice

https://eeaonline.eea.state.ma.us/portal/dep/cso-data-portal/detail…

Revision of

none (first record)

Revised by

ma-massdep:91d53ba4-45b8-4e6a-b46b-f1a0276f1709

{
  "incidentId": "313944f6-9ad0-4551-9d05-1537eda60be6",
  "incidentNumber": "26017810",
  "incidentDate": "2026-10-11T00:00:00",
  "incidentTime": "20:00",
  "amPm": null,
  "reporterClass": "Public Notification Report",
  "eventType": "CSO – UnTreated",
  "permiteeClass": "CSO",
  "permiteeName": "CITY OF CHELSEA",
  "permiteeId": "MA0101877",
  "outfallId": "CHE008",
  "municipality": "CHELSEA",
  "reportingType": "Initial-Ceased",
  "location": "NORTHERN EDGE OF GULF BULK OIL STORAGE",
  "latitude": null,
  "longitude": null,
  "waterBody": "CHELSEA RIVER",
  "waterBodyDescription": null,
  "volumnOfEvent": "",
  "rainfallData": "",
  "hours": "",
  "minutes": "",
  "month": null,
  "year": null,
  "additionalInformation": null,
  "submittedDate": "2026-10-20T18:34:03.613",
  "parentIncidentId": null,
  "_report_class": "Public Notification Report",
  "_tz_assumed": "America/New_York (portal gives local clock time without zone)",
  "_ended_note": "reported ceased; the portal gives no cessation time",
  "_coords": "MassDEP CSOs layer DEP_OUTFL_ CHE008 (locations are estimates)",
  "_water": {
    "no_slug": [
      "CHELSEA RIVER (Chelsea Creek - no slug)",
      "CHELSEA RIVER (Chelsea Creek - no slug)"
    ]
  },
  "_advice_source": "required wording of 314 CMR 16.04(10)(g); the permittee's own advisory is only in an attachment the portal will not serve",
  "_ended_at_basis": "from Verified Data Report 26017867: its start + verified duration"
}