Maine / Dischargers /
City of Portland (Department of Public Works / Water Resources)
CSO · Maine · Portland
- NPDES permit
- ME0101435
- Outfalls
- 12 with coordinates in the registry (the state's layer lists 7)
- Receiving waters
- Back Cove; Capisic Brook; Portland Harbor; Nason Brook to Fore River
- Tracked waters
- Casco Bay, ME, Fore River, ME
- Events tracked
- 0 discharges
- Volume reported
- no volumes reported
Source: discharger record from the project's research and EPA ECHO (dischargers.json); counts from the 0 event records below, as of 2026-11-02 11:56 UTC.
How it tells the public
No CSO event page or alert found on portlandmaine.gov (city page URLs tried returned 404). Signs at outfalls per permit. Per-event, per-outfall data exist in the annual 'CSO Activity and Volumes' spreadsheets filed with DEP; CBEP obtained 2015-2019 Portland files by email from PWD (github.com/CBEP-SoCB-Details/Casco_Bay_CSOs).
Source: the project's research on each operator's notification channel (research/<state>/dischargers.json), checked by fetching the operator's pages.
Outfalls
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.
12 outfalls in the registry
- 006 JOHANSEN STREET · CSO · Back Cove
- 013 FOREST AT BELMONT · CSO · Portland Harbor, Back Cove, Ca
- 014 Coyles Gulley · CLS · Back Cove
- 017 PREBLE AT MARGINAL · CSO · Portland Harbor, Back Cove, Ca
- 018 FRANKLIN AT MARGINAL · CSO · Portland Harbor, Back Cove, Ca
- 019 Fox at Anderson · CLS · Back Cove
- 024 FRANKLIN AT MIDDLE · CSO · Portland Harbor, Back Cove, Ca
- 026 MAPLE STREET · CSO · Portland Harbor
- 036 Capisic Pond Dam · CLS · Capisic Brook
- 039 ROWE AVENUE · CSO · Fore River
- 042 WARREN 60 · CSO · Capisic Pond
- 043 Warren Avenue · CLS · Capisic Brook · not on a tracked water
Source: EPA ECHO CSO outfall inventory matched to waters (data/outfalls-ne.json).
Event history
| Start | End | Water | Outfall | Type | Volume | Source | Links |
|---|---|---|---|---|---|---|---|
| 2024 | 2025 | Casco Bay, ME | not stated | Annual total | 115.31 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2025, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2023 | 2024 | Casco Bay, ME | not stated | Annual total | 290.21 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2024, published Jun 29, 2025, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2022 | 2023 | Casco Bay, ME | not stated | Annual total | 368.66 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2023, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2021 | 2022 | Casco Bay, ME | not stated | Annual total | 163.96 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2022, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2020 | 2021 | Casco Bay, ME | not stated | Annual total | 194.47 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2021, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2019 | 2020 | Casco Bay, ME | not stated | Annual total | 178.74 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2020, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2018 | 2019 | Casco Bay, ME | not stated | Annual total | 184.45 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2019, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2017 | 2018 | Casco Bay, ME | not stated | Annual total | 283.61 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2018, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2016 | 2017 | Casco Bay, ME | not stated | Annual total | 175.68 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2017, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2015 | 2016 | Casco Bay, ME | not stated | Annual total | 318.36 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2016, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2014 | 2015 | Casco Bay, ME | not stated | Annual total | 254.66 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2015, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2013 | 2014 | Casco Bay, ME | not stated | Annual total | 414.42 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2014, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2012 | 2013 | Casco Bay, ME | not stated | Annual total | 179.4 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2013, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2011 | 2012 | Casco Bay, ME | not stated | Annual total | 704.32 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2012, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| 2010 | 2011 | Casco Bay, ME | not stated | Annual total | 496.29 million gal | Maine DEP CSO Status Report via Maine DEP Maine Combined Sewer Overflow Status Report (annual; latest = 2025 report, June 2026), record ME0101435:2011, published Jun 29, 2026, 8:00 PM EDT, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
History
Reported yearly totals: Maine DEP CSO status reports (annual totals)
Maine DEP reports one total per community and year (all of its CSO outfalls); it is shown in full on each water the community's outfalls reach. Event-days: calendar days with any CSO discharge in the community. Source: Maine DEP CSO status reports (annual totals). Covered 2011-01-01 to 2025-12-31.
Reported volume
Gallons per year.
Show table
| Year | Reported volume |
|---|---|
| 2011 | 496,288,000 gal |
| 2012 | 704,319,257 gal |
| 2013 | 179,403,901 gal |
| 2014 | 414,421,500 gal |
| 2015 | 254,663,330 gal |
| 2016 | 318,359,691 gal |
| 2017 | 175,675,000 gal |
| 2018 | 283,612,831 gal |
| 2019 | 184,453,600 gal |
| 2020 | 178,744,981 gal |
| 2021 | 194,468,501 gal |
| 2022 | 163,964,790 gal |
| 2023 | 368,662,200 gal |
| 2024 | 290,214,400 gal |
| 2025 | 115,308,100 gal |
Days with a CSO discharge
Days per year.
Show table
| Year | Days with a CSO discharge |
|---|---|
| 2011 | 88 |
| 2012 | 70 |
| 2013 | 63 |
| 2014 | 75 |
| 2015 | 58 |
| 2016 | 56 |
| 2017 | 38 |
| 2018 | 49 |
| 2019 | 46 |
| 2020 | 41 |
| 2021 | 61 |
| 2022 | 52 |
| 2023 | 37 |
| 2024 | 48 |
| 2025 | 38 |
How these charts are counted
Discharge events are counted once: where a source publishes both public notices and verified reports (MassDEP, Vermont DEC), a discharger's month with any verified report counts its verified reports only, and other months count notices. Revisions are folded into the record they revise, and EPA copies of a state report are not counted twice. Monthly and yearly totals (Maine DEP, EPA discharge monitoring reports, Portsmouth) are shown on their own and never added to the event counts. Hours under advisory follow the map's red rules. A muted band marks periods no source covers: a gap there is missing data, not a quiet month.