Combined sewer overflow: BOSTON WATER & SEWER COMMISSION, Sep 27, 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 (eeaonline.eea.state.ma.us/dep/CSOAPI/api/), record fe7415ea-bc1a-4e57-8df7-fd5817f8485b, published Oct 13, 2026, 10:41 AM EDT, retrieved 2026-11-02 11:54 UTC · notice

Revised. Revised by ma-massdep:2d127e90-9295-4b15-bfe1-2859bb638696. The newest revision is the one used for the map. see the revision

A report is not a test of the water. See how statuses are worked out.

1. The reported outfall

Outfall reported by BOSTON WATER & SEWER COMMISSION (MA0101192 outfall BOS019): “JUST NW OF TOBIN BRIDGE AND 16TH ST”. Location: 42.37996, -71.05102, from the state's or EPA's outfall layer.

2. Waters named in the notice

The notice names: “LITTLE MYSTIC CHANNEL”. Not placed on a tracked water.

3. Modeled downstream reach

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

Source: water outlines from OpenBoatLaunch and OpenStreetMap contributors (ODbL); outfalls from EPA ECHO and the state outfall layers; modeled reaches computed by DirtyWaterWatch from USGS NLDI, NHDPlus and the nearest USGS gauge (Jobson 1996); basemap OpenFreeMap and OpenMapTiles.

Open on the main map

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: Sep 27, 2026, 2:35 PM EDT
Ended: Sep 27, 2026, 4:05 PM EDT
Precision: Known to the minute
Reported to the source: not given
Published: Oct 13, 2026, 10:41 AM 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.”
BOSTON WATER & SEWER COMMISSION (MassDEP sewage notification portal) · 314 CMR 16.04(10)(g)

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: fe7415ea-bc1a-4e57-8df7-fd5817f8485b
Original notice: https://eeaonline.eea.state.ma.us/portal/dep/cso-data-portal/detail…
Revision of: none (first record)
Revised by: ma-massdep:2d127e90-9295-4b15-bfe1-2859bb638696

Every field of the record

All fields of event ma-massdep:fe7415ea-bc1a-4e57-8df7-fd5817f8485b
`event_id`	ma-massdep:fe7415ea-bc1a-4e57-8df7-fd5817f8485b
`source_id`	ma-massdep
`source_record_id`	fe7415ea-bc1a-4e57-8df7-fd5817f8485b
`parent_event_id`	null
`event_type`	cso
`status`	ended
`discharger_id`	ma-bwsc
`discharger_name`	BOSTON WATER & SEWER COMMISSION
`npdes_permit`	MA0101192
`outfall_id`	BOS019
`outfall_name`	JUST NW OF TOBIN BRIDGE AND 16TH ST
`waterbody_text`	LITTLE MYSTIC CHANNEL
`water_slugs`	[]
`water_match`	none
`lat`	42.379965
`lon`	-71.051018
`coord_source`	outfall_layer
`coord_precision_m`	null
`started_at`	2026-09-27T14:35:00-04:00
`ended_at`	2026-09-27T16:05:00-04:00
`time_precision`	minute
`reported_at`	null
`published_at`	2026-10-13T10:41:58-04:00
`source_updated_at`	null
`fetched_at`	2026-11-02T11:54:49Z
`material`	CSO – UnTreated
`volume_gal`	null
`volume_text`	null
`estimate_flag`	unknown
`authority`	BOSTON WATER & SEWER COMMISSION (MassDEP sewage notification portal)
`advice_text`	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_hours`	48
`advice_window_basis`	314 CMR 16.04(10)(g)
`source_url`	https://eeaonline.eea.state.ma.us/portal/dep/cso-data-portal/details/fe7415ea-bc1a-4e57-8df7-fd5817f8485b
`parse_error`	null
`fixture`	false
`superseded`	revised by ma-massdep:2d127e90-9295-4b15-bfe1-2859bb638696
`file`	events/ma-massdep~3Afe7415ea-bc1a-4e57-8df7-fd5817f8485b.json
`duplicate_of`	null
`placement_note`	null
`unplaced_reason`	null
`set_aside`	null
`reach`	null
`reach_band`	null

The source's record (raw)

{
  "incidentId": "fe7415ea-bc1a-4e57-8df7-fd5817f8485b",
  "incidentNumber": "26017632",
  "incidentDate": "2026-09-27T00:00:00",
  "incidentTime": "14:35",
  "amPm": null,
  "reporterClass": "Public Notification Report",
  "eventType": "CSO – UnTreated",
  "permiteeClass": "CSO",
  "permiteeName": "BOSTON WATER & SEWER COMMISSION",
  "permiteeId": "MA0101192",
  "outfallId": "BOS019",
  "municipality": "BOSTON",
  "reportingType": "Initial-Ceased",
  "location": "JUST NW OF TOBIN BRIDGE AND 16TH ST",
  "latitude": null,
  "longitude": null,
  "waterBody": "LITTLE MYSTIC CHANNEL",
  "waterBodyDescription": null,
  "volumnOfEvent": "",
  "rainfallData": "",
  "hours": "",
  "minutes": "",
  "month": null,
  "year": null,
  "additionalInformation": "An automatic public notification was not distributed within two hours for this CSO activation at BOS019. This was due to a failed sensor during nor'easter conditions on 9/26 & 9/27 . This resulted in the event not being recognized at the time. Upon review of data, it was discovered that there was a CSO event at this location on 9/27/26. The consultant went out and repaired the sensor immediately (pictures attached).",
  "submittedDate": "2026-10-13T10:41:58.47",
  "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_ BOS019 (locations are estimates)",
  "_water": {
    "no_slug": [
      "LITTLE MYSTIC CHANNEL (Boston Harbor - no slug)",
      "LITTLE MYSTIC CHANNEL (Boston Harbor - 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 26017836: its start + verified duration"
}

Personal fields (names, emails, phone numbers of staff) are removed from raw records before they are stored.