Combined sewer overflow: BOSTON WATER & SEWER COMMISSION, May 19, 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 21b203bc-daa1-44b7-8df8-ba34511c6861, published Jun 11, 2026, 4:13 PM EDT, retrieved 2026-11-02 10:58 UTC · notice

Colours no water as of Nov 2, 2026, 6:56 AM EST: the windows on the methods page have passed, or the record has no time to count from.

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 BOS010): “WEST OF BORDER ST ON EAST BANK BOS INNER HRBR”. Location: 42.37344, -71.04217, from the state's or EPA's outfall layer.

2. Waters named in the notice

The notice names: “BOSTON INNER HARBOR”. We place it on Mystic River, MA. Matched by the outfall's ID in the outfall registry, which places each outfall on a water.

outfall MA0101192 010 (geometry, 320 m)

3. Modeled downstream reach

No modeled reach for this record in this build.

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: May 19, 2026, 6:40 PM EDT
Ended: May 20, 2026, 9:00 AM EDT
Precision: Known to the minute
Reported to the source: not given
Published: Jun 11, 2026, 4:13 PM EDT
Source last updated: not given
We fetched it: 2026-11-02 10:58 UTC

What and how much

Type: Combined sewer overflow
Status in the record: Ended (as reported)
Material: “CSO – UnTreated”
Volume: 223,567 gal (not stated whether estimated or measured)
Volume in the source's words: “223567”

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: 21b203bc-daa1-44b7-8df8-ba34511c6861
Original notice: https://eeaonline.eea.state.ma.us/portal/dep/cso-data-portal/detail…
Revision of: ma-massdep:9fd4f718-7abe-4b16-bd02-f05a41a83298
Revised by: no later revision

Every field of the record

All fields of event ma-massdep:21b203bc-daa1-44b7-8df8-ba34511c6861
`event_id`	ma-massdep:21b203bc-daa1-44b7-8df8-ba34511c6861
`source_id`	ma-massdep
`source_record_id`	21b203bc-daa1-44b7-8df8-ba34511c6861
`parent_event_id`	ma-massdep:9fd4f718-7abe-4b16-bd02-f05a41a83298
`event_type`	cso
`status`	ended
`discharger_id`	ma-bwsc
`discharger_name`	BOSTON WATER & SEWER COMMISSION
`npdes_permit`	MA0101192
`outfall_id`	BOS010
`outfall_name`	WEST OF BORDER ST ON EAST BANK BOS INNER HRBR
`waterbody_text`	BOSTON INNER HARBOR
`water_slugs`	["mystic-river-ma"]
`water_match`	outfall_registry
`lat`	42.373442
`lon`	-71.042169
`coord_source`	outfall_layer
`coord_precision_m`	null
`started_at`	2026-05-19T18:40:00-04:00
`ended_at`	2026-05-20T09:00:00-04:00
`time_precision`	minute
`reported_at`	null
`published_at`	2026-06-11T16:13:17-04:00
`source_updated_at`	null
`fetched_at`	2026-11-02T10:58:11Z
`material`	CSO – UnTreated
`volume_gal`	223567
`volume_text`	223567
`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/21b203bc-daa1-44b7-8df8-ba34511c6861
`parse_error`	null
`fixture`	false
`reach`	MA0101192-010
`file`	events/ma-massdep~3A21b203bc-daa1-44b7-8df8-ba34511c6861.json
`duplicate_of`	null
`placement_note`	outfall MA0101192 010 (geometry, 320 m)
`unplaced_reason`	null
`set_aside`	null
`superseded`	null
`reach_band`	null

The source's record (raw)

{
  "incidentId": "21b203bc-daa1-44b7-8df8-ba34511c6861",
  "incidentNumber": "26016287",
  "incidentDate": "2026-05-19T00:00:00",
  "incidentTime": "18:40",
  "amPm": null,
  "reporterClass": "Verified Data Report",
  "eventType": "CSO – UnTreated",
  "permiteeClass": "CSO",
  "permiteeName": "BOSTON WATER & SEWER COMMISSION",
  "permiteeId": "MA0101192",
  "outfallId": "BOS010",
  "municipality": "BOSTON",
  "reportingType": null,
  "location": "WEST OF BORDER ST ON EAST BANK BOS INNER HRBR",
  "latitude": null,
  "longitude": null,
  "waterBody": "BOSTON INNER HARBOR",
  "waterBodyDescription": null,
  "volumnOfEvent": "223567",
  "rainfallData": "0.20",
  "hours": "14",
  "minutes": "20",
  "month": null,
  "year": null,
  "additionalInformation": null,
  "submittedDate": "2026-06-11T16:13:17.71",
  "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 14 h 20 min (Verified Data Report)",
  "_coords": "MassDEP CSOs layer DEP_OUTFL_ BOS010 (locations are estimates)",
  "_water": {
    "echo_candidate": {
      "slug": "mystic-river-ma",
      "match": "geometry",
      "why_not": "geometry only, name differs"
    },
    "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 26016170; start times 0 min apart"
}

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