Combined sewer overflow: MASSACHUSETTS WATER RESOURCES AUTHORITY, Jul 29, 2026

Ended (as reported) · MASSACHUSETTS WATER RESOURCES AUTHORITY (MassDEP sewage notification portal)

Source: MASSACHUSETTS WATER RESOURCES AUTHORITY (MassDEP sewage notification portal) via MassDEP CSO API behind the portal (eeaonline.eea.state.ma.us/dep/CSOAPI/api/), record 70ae5118-fa37-4133-8ebc-a8c543026578, published Aug 5, 2026, 2:12 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 MASSACHUSETTS WATER RESOURCES AUTHORITY (MA0103284 outfall MWR205): “EAST BNK MYSTIC 150 FT SW OF MDC LOCKS”. Location: 42.39405, -71.07606, from the state's or EPA's outfall layer.

2. Waters named in the notice

The notice names: “MYSTIC RIVER”. We place it on Mystic River, MA. Matched by the name of the water in the source record.

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: Jul 29, 2026, 11:53 PM EDT
Ended: Jul 30, 2026, 4:22 AM EDT
Precision: Known to the minute
Reported to the source: not given
Published: Aug 5, 2026, 2:12 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 – Treated”
Volume: 960,000 gal (not stated whether estimated or measured)
Volume in the source's words: “960000”

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.”
MASSACHUSETTS WATER RESOURCES AUTHORITY (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: 70ae5118-fa37-4133-8ebc-a8c543026578
Original notice: https://eeaonline.eea.state.ma.us/portal/dep/cso-data-portal/detail…
Revision of: ma-massdep:98b5027c-ed2f-46dd-abe9-e4ee1295801f
Revised by: no later revision

Every field of the record

All fields of event ma-massdep:70ae5118-fa37-4133-8ebc-a8c543026578
`event_id`	ma-massdep:70ae5118-fa37-4133-8ebc-a8c543026578
`source_id`	ma-massdep
`source_record_id`	70ae5118-fa37-4133-8ebc-a8c543026578
`parent_event_id`	ma-massdep:98b5027c-ed2f-46dd-abe9-e4ee1295801f
`event_type`	cso
`status`	ended
`discharger_id`	ma-mwra
`discharger_name`	MASSACHUSETTS WATER RESOURCES AUTHORITY
`npdes_permit`	MA0103284
`outfall_id`	MWR205
`outfall_name`	EAST BNK MYSTIC 150 FT SW OF MDC LOCKS
`waterbody_text`	MYSTIC RIVER
`water_slugs`	["mystic-river-ma"]
`water_match`	name
`lat`	42.394053
`lon`	-71.076057
`coord_source`	outfall_layer
`coord_precision_m`	null
`started_at`	2026-07-29T23:53:00-04:00
`ended_at`	2026-07-30T04:22:00-04:00
`time_precision`	minute
`reported_at`	null
`published_at`	2026-08-05T14:12:37-04:00
`source_updated_at`	null
`fetched_at`	2026-11-02T10:58:11Z
`material`	CSO – Treated
`volume_gal`	960000
`volume_text`	960000
`estimate_flag`	unknown
`authority`	MASSACHUSETTS WATER RESOURCES AUTHORITY (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/70ae5118-fa37-4133-8ebc-a8c543026578
`parse_error`	null
`fixture`	false
`reach`	MA0103284-MWR205
`file`	events/ma-massdep~3A70ae5118-fa37-4133-8ebc-a8c543026578.json
`duplicate_of`	null
`placement_note`	null
`unplaced_reason`	null
`set_aside`	null
`superseded`	null
`reach_band`	null

The source's record (raw)

{
  "incidentId": "70ae5118-fa37-4133-8ebc-a8c543026578",
  "incidentNumber": "26017083",
  "incidentDate": "2026-07-29T00:00:00",
  "incidentTime": "23:53",
  "amPm": null,
  "reporterClass": "Verified Data Report",
  "eventType": "CSO – Treated",
  "permiteeClass": "CSO",
  "permiteeName": "MASSACHUSETTS WATER RESOURCES AUTHORITY",
  "permiteeId": "MA0103284",
  "outfallId": "MWR205",
  "municipality": "SOMERVILLE",
  "reportingType": null,
  "location": "EAST BNK MYSTIC 150 FT SW OF MDC LOCKS",
  "latitude": null,
  "longitude": null,
  "waterBody": "MYSTIC RIVER",
  "waterBodyDescription": null,
  "volumnOfEvent": "960000",
  "rainfallData": "1.20",
  "hours": "4",
  "minutes": "29",
  "month": null,
  "year": null,
  "additionalInformation": null,
  "submittedDate": "2026-08-05T14:12:37.063",
  "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 4 h 29 min (Verified Data Report)",
  "_coords": "MassDEP CSOs layer DEP_OUTFL_ MWR205 (locations are estimates)",
  "_water": {
    "via": "crosswalk on portal waterbody",
    "text": "MYSTIC RIVER",
    "confidence": "high"
  },
  "_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 26016910; start times 1 min apart"
}

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