Massachusetts / Reports /

Combined sewer overflow (CSO) reported — CITY OF SOMERVILLE, Jul 22, 2026

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

Source: CITY OF SOMERVILLE (MassDEP sewage notification portal) via MassDEP CSO API behind the portal, record 0f673e83-57ac-45ad-b3e8-bd26684be44f, published Aug 13, 2026, 9:02 AM 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: CITY OF SOMERVILLE (federal wastewater discharge permit, NPDES, MA0101982). Outlet: SOM001A “100 FT BEYOND END OF MATIGNON RD”. Location: 42.40243, -71.13512; 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: “ALEWIFE BROOK”. DirtyWaterWatch links this report to Alewife Brook, MA. 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

Jul 22, 2026, 4:25 PM EDT

Ended

Jul 22, 2026, 4:35 PM EDT

Detail provided by the source

Times known to the minute

Reported to the source

not given

Published

Aug 13, 2026, 9:02 AM 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

106,000 gallons (not stated whether estimated or measured)

Volume as reported

“106000”

Advice from CITY OF SOMERVILLE (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

0f673e83-57ac-45ad-b3e8-bd26684be44f

Original notice

Read the original notice

Earlier version

Read the earlier version

Later versions

None

{
  "incidentId": "0f673e83-57ac-45ad-b3e8-bd26684be44f",
  "incidentNumber": "26017182",
  "incidentDate": "2026-07-22T00:00:00",
  "incidentTime": "16:25",
  "amPm": null,
  "reporterClass": "Verified Data Report",
  "eventType": "CSO – UnTreated",
  "permiteeClass": "CSO",
  "permiteeName": "CITY OF SOMERVILLE",
  "permiteeId": "MA0101982",
  "outfallId": "SOM001A",
  "municipality": "CAMBRIDGE",
  "reportingType": null,
  "location": "100 FT BEYOND END OF MATIGNON RD",
  "latitude": null,
  "longitude": null,
  "waterBody": "ALEWIFE BROOK",
  "waterBodyDescription": null,
  "volumnOfEvent": "106000",
  "rainfallData": "0.66",
  "hours": "0",
  "minutes": "10",
  "month": null,
  "year": null,
  "additionalInformation": null,
  "submittedDate": "2026-08-13T09:02:19.693",
  "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 10 min (Verified Data Report)",
  "_coords": "MassDEP CSOs layer DEP_OUTFL_ SOM001A (locations are estimates)",
  "_water": {
    "no_slug": [
      "ALEWIFE BROOK (tributary of Mystic - no slug)",
      "ALEWIFE BROOK (tributary of Mystic - no 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 26016832; start times 0 min apart"
}