Massachusetts / Reports /

Combined sewer overflow (CSO) reported — BOSTON WATER & SEWER COMMISSION, Jun 18, 2026

Ended (as reported) · BOSTON WATER & SEWER COMMISSION (MassDEP sewage notification portal)

Source: BOSTON WATER & SEWER COMMISSION (MassDEP sewage notification portal) via MassDEP CSO API behind the portal, record 6861dd19-4091-4495-b831-ef268e7aaba4, published Jul 6, 2026, 3:13 PM EDT, retrieved 2026-11-02 10:58 UTC · Read the original notice

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1. Reported wastewater outlet

Operator named in the record: BOSTON WATER & SEWER COMMISSION (federal wastewater discharge permit, NPDES, MA0101192). Outlet: BOS003 “SW CORNER OF LOGAN NW OF 90”. Location: 42.35785, -71.02774; location source: from the state's or EPA's outfall layer.

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

2. Waters named in the notice

The notice names: “BOSTON INNER HARBOR”. DirtyWaterWatch links this report to Boston Inner Harbor, MA. Match basis: the water named in the report.

3. Estimated downstream stretch

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

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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

Jun 18, 2026, 7:00 PM EDT

Ended

Jun 18, 2026, 7:05 PM EDT

Detail provided by the source

Times known to the minute

Reported to the source

not given

Published

Jul 6, 2026, 3:13 PM EDT

Source last updated

not given

Last retrieved by DirtyWaterWatch

2026-11-02 10:58 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

“CSO – UnTreated”

Volume

9,264 gallons (not stated whether estimated or measured)

Volume as reported

“9264”

Advice from BOSTON WATER & SEWER COMMISSION (MassDEP sewage notification portal)

“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 period

48 hours

Basis

314 CMR 16.04(10)(g)

Source and versions

Source

MassDEP CSO API behind the portal

Source record number

6861dd19-4091-4495-b831-ef268e7aaba4

Original notice

Read the original notice

Earlier version

Read the earlier version

Later versions

None

{
  "incidentId": "6861dd19-4091-4495-b831-ef268e7aaba4",
  "incidentNumber": "26016577",
  "incidentDate": "2026-06-18T00:00:00",
  "incidentTime": "19:00",
  "amPm": null,
  "reporterClass": "Verified Data Report",
  "eventType": "CSO – UnTreated",
  "permiteeClass": "CSO",
  "permiteeName": "BOSTON WATER & SEWER COMMISSION",
  "permiteeId": "MA0101192",
  "outfallId": "BOS003",
  "municipality": "BOSTON",
  "reportingType": null,
  "location": "SW CORNER OF LOGAN NW OF 90",
  "latitude": null,
  "longitude": null,
  "waterBody": "BOSTON INNER HARBOR",
  "waterBodyDescription": null,
  "volumnOfEvent": "9264",
  "rainfallData": "0.37",
  "hours": "0",
  "minutes": "5",
  "month": null,
  "year": null,
  "additionalInformation": "Public Notification Report is late because the event did not meet the time threshold of the notification system in place. Upon review of the data, this was determined to be an actual CSO event, so public advisory notification was submitted beyond the 18-hour report window.",
  "submittedDate": "2026-07-06T15:13:31.683",
  "parentIncidentId": null,
  "_report_class": "Verified Data Report",
  "_tz_assumed": "America/New_York (portal gives local clock time without zone)",
  "_ended_at_basis": "computed: started_at + verified duration 0 h 5 min (Verified Data Report)",
  "_coords": "MassDEP CSOs layer DEP_OUTFL_ BOS003 (locations are estimates)",
  "_water": {
    "no_slug": [
      "BOSTON INNER HARBOR (no Boston Harbor slug)",
      "BOSTON INNER HARBOR (no Boston Harbor slug)"
    ]
  },
  "_volume_note": "verified by permittee, reported to MassDEP (metered or modelled not stated)",
  "_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",
  "_link_basis": "same permittee and outfall as notice 26016415; start times 0 min apart"
}