City of Portsmouth DPW Wastewater Division (Peirce Island WWTF and 3 CSOs)
CSO · New Hampshire · Portsmouth, New Castle
- NPDES permit
- NH0100234
- Outfalls
- 4 with coordinates in the registry (the state's layer lists 3)
- Receiving waters
- South Mill Pond (tidal, to Piscataqua River); Piscataqua River
- Tracked waters
- Piscataqua River, NH, Portsmouth Harbor, NH
- Events tracked
- 188 discharges · latest Dec 30, 2025, 6:50 PM EST
- Volume reported
- 197,608,480 gallons across the 188 discharges that give a volume
Source: discharger record from the project's research and EPA ECHO (dischargers.json); counts from the 188 event records below, as of 2026-11-02 11:56 UTC.
How it tells the public
Page https://www.portsmouthnh.gov/publicworks/wastewater/combined-sewer-overflows-cso. It has a 'CSO Dashboard' iframe (https://appservices.flowassessment.com/mapserver/cso_map.html?project=Portsmouth). Page text: 'If an overflow is detected in any of the measuring devices in the City's three active CSO outfall locations, it will show up here in real time.' Email: 'sign up for our email list below. Your email will be added to a list in which our measuring devices will email you directly as events occur.' The embedded Mailchimp form posts to cityofportsmouth.us2.list-manage.com (list id 5e033c4988); not submitted. The page also has a monthly volume table (10A/10B/013) with monthly PDF memos back to 2015. Legacy X/Twitter @PortsmouthCSOs (auto-tweets since 2018) is no longer linked from the page.
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.
4 outfalls in the registry
- 012 Marcy Street · CLS · Piscataqua River
- 013 Deer Street · CSO · Portsmouth Harbor
- 10A Parrot Avenue · CSO · Portsmouth Harbor
- 10B Parrot Avenue · CSO · Portsmouth Harbor
Source: EPA ECHO CSO outfall inventory matched to waters (data/outfalls-ne.json).
Event history
| Start | End | Water | Outfall | Type | Volume | Source | Links |
|---|---|---|---|---|---|---|---|
| Dec 30, 2025, 6:50 PM EST | Dec 30, 2025, 7:50 PM EST | “South Mill Pond via the MS4 System” (not placed) | not stated | Sanitary sewer overflow | 10 gal | EPA ECHO Sewer Overflow and Bypass Event report (reported to regulators) via ECHO NPDES Sewer Overflow and Bypass Event Dataset (eRule Phase 2, current versions), record NH0100234:1:1, reported Dec 30, 2025, 7:00 PM EST, retrieved 2026-11-02 11:54 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| May 2025 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 55,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2025-05:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2024 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 149,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2024-06:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| April 2024 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 1.13 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2024-04:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| March 2024 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 866,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2024-03:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2024 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 4.44 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2024-01:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2024 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 3.67 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2024-01:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2023 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 2.4 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-09:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2023 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 21,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-09:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| August 2023 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 2.45 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-08:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| August 2023 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 37,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-08:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| August 2023 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 59,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-08:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2023 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 826,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-07:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2023 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 3,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-07:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2023 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 24,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-07:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2023 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 14,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-06:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| May 2023 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 2.19 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-05:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| April 2023 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 634,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-04:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| March 2023 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 71,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-03:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2023 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 4.17 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-01:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2023 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 216,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-01:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2023 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 140,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2023-01:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| November 2022 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 1,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-11:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2022 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 210,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-10:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2022 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 13,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-10:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2022 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 75,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-09:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2022 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 2,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-09:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| August 2022 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 144,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-08:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2022 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 30,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-07:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2022 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 32,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-06:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| May 2022 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 27,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-05:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| April 2022 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 102,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2022-04:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| November 2021 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 36,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2021-11:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2021 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 573,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2021-10:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2021 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 15,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2021-10:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2021 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 849,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2021-10:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2021 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 30,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2021-09:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| August 2021 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 4,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2021-08:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2021 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 121,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2021-07:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2021 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 312,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2021-07:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| December 2020 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 3,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-12:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| November 2020 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 40,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-11:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2020 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 9,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-10:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2020 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 5,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-09:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| August 2020 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 2,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-08:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2020 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 40,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-07:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2020 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 3,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-07:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2020 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 372,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-06:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2020 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 117,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-06:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2020 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 319,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-06:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2020 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 6,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2020-01:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| December 2019 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 433,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-12:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| December 2019 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 385,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-12:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| December 2019 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 974,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-12:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2019 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 1,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-10:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| August 2019 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 38,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-08:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2019 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 14,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-07:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2019 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 198,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-06:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2019 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 10,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-06:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2019 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 19,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-06:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| February 2019 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 1.01 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-02:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| February 2019 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 46,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-02:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2019 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 416,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2019-01:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| November 2018 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 125,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-11:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2018 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 2.59 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-09:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2018 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 390,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-09:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2018 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 957,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-09:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| August 2018 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 78,200 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-08:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2018 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 469,900 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-07:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2018 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 929,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-07:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2018 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 149,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-07:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| April 2018 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 1.6 million gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-04:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| April 2018 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 9,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-04:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| April 2018 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 512,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2018-04:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2017 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 241,100 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2017-10:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| August 2017 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 700 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2017-08:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2017 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 161,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2017-06:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| May 2017 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 401,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2017-05:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| May 2017 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 8,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2017-05:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| April 2017 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 401,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2017-04:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| April 2017 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 15,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2017-04:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| February 2017 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 2,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2017-02:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| November 2016 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 150,200 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-11:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2016 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 679,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-10:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2016 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 9,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-10:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2016 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 147,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-10:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2016 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 521,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-07:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2016 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 21,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-07:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| July 2016 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 35,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-07:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2016 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 40,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-06:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| June 2016 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 52,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-06:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| February 2016 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 775,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-02:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| February 2016 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 12,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-02:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2016 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 844,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-01:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2016 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 10,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-01:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| January 2016 | ended, time not reported | Piscataqua River, NH | 013 Deer Street | Combined sewer overflow | 198,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2016-01:013, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| December 2015 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 13,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2015-12:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| October 2015 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 6,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2015-10:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2015 | ended, time not reported | Portsmouth Harbor, NH | 10A Parrot Avenue | Combined sewer overflow | 804,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2015-09:10A, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
| September 2015 | ended, time not reported | Portsmouth Harbor, NH | 10B Parrot Avenue | Combined sewer overflow | 165,000 gal | City of Portsmouth DPW (CSO page, monthly summary table) via nh-permittees, record portsmouth:2015-09:10B, the source gives no report time, retrieved 2026-11-02 11:55 UTC · notice | record below · Map |
Full record (older than 180 days, so no page of its own) | |||||||
Showing the newest 100 events of 188 events. See them all with filters.
History
- Discharge events, last 12 months1Dec 2025 to Nov 2026; partly covered or sparse source
- Days with a discharge, last 12 months1Dec 2025 to Nov 2026; partly covered or sparse source
- Hours under advisory, last 12 months73Dec 2025 to Nov 2026; on this discharger's reports; partly covered or sparse source
Discharge events per month
1 events, Jan 2022 to Nov 2026.
- Combined sewer overflow
- Sanitary sewer overflow
- Bypass, blended or other
- No source
- Partly covered or sparse source
No source covers 2022-01 to 2022-04. EPA ECHO sewer overflow records are sparse (only what permittees file with EPA). Some dischargers here report only monthly or yearly totals; those are shown under reported totals, not counted here.
Source: EPA ECHO sewer overflow events. Covered 2022-05-03 to 2026-11-02.
Show table
| Month | Combined sewer overflow | Sanitary sewer overflow | Bypass, blended or other | Total | Counted from | Coverage |
|---|---|---|---|---|---|---|
| Jan 2022 | 0 | 0 | 0 | 0 | No source | |
| Feb 2022 | 0 | 0 | 0 | 0 | No source | |
| Mar 2022 | 0 | 0 | 0 | 0 | No source | |
| Apr 2022 | 0 | 0 | 0 | 0 | No source | |
| May 2022 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jun 2022 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jul 2022 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Aug 2022 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Sep 2022 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Oct 2022 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Nov 2022 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Dec 2022 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jan 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Feb 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Mar 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Apr 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| May 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jun 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jul 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Aug 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Sep 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Oct 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Nov 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Dec 2023 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jan 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Feb 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Mar 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Apr 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| May 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jun 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jul 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Aug 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Sep 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Oct 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Nov 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Dec 2024 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jan 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Feb 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Mar 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Apr 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| May 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jun 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jul 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Aug 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Sep 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Oct 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Nov 2025 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Dec 2025 | 0 | 1 | 0 | 1 | Source records | Partly covered or sparse source |
| Jan 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Feb 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Mar 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Apr 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| May 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jun 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Jul 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Aug 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Sep 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Oct 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source | |
| Nov 2026 | 0 | 0 | 0 | 0 | Partly covered or sparse source |
Hours under advisory per month
Hours this discharger's reports put a water under an advisory, by the map's red rules.
- Advisory in effect
- No source
- Partly covered or sparse source
No source covers 2022-01 to 2022-04. Official beach and cyanobacteria advisories are counted on water pages only. EPA ECHO sewer overflow records are sparse (only what permittees file with EPA).
Source: EPA ECHO sewer overflow events. Covered 2022-05-03 to 2026-11-02.
Show table
| Month | Hours under advisory | From discharge windows | Hours in month | Coverage |
|---|---|---|---|---|
| Jan 2022 | 0 | 0 | 744 | No source |
| Feb 2022 | 0 | 0 | 672 | No source |
| Mar 2022 | 0 | 0 | 744 | No source |
| Apr 2022 | 0 | 0 | 720 | No source |
| May 2022 | 0 | 0 | 744 | Partly covered or sparse source |
| Jun 2022 | 0 | 0 | 720 | Partly covered or sparse source |
| Jul 2022 | 0 | 0 | 744 | Partly covered or sparse source |
| Aug 2022 | 0 | 0 | 744 | Partly covered or sparse source |
| Sep 2022 | 0 | 0 | 720 | Partly covered or sparse source |
| Oct 2022 | 0 | 0 | 744 | Partly covered or sparse source |
| Nov 2022 | 0 | 0 | 720 | Partly covered or sparse source |
| Dec 2022 | 0 | 0 | 744 | Partly covered or sparse source |
| Jan 2023 | 0 | 0 | 744 | Partly covered or sparse source |
| Feb 2023 | 0 | 0 | 672 | Partly covered or sparse source |
| Mar 2023 | 0 | 0 | 744 | Partly covered or sparse source |
| Apr 2023 | 0 | 0 | 720 | Partly covered or sparse source |
| May 2023 | 0 | 0 | 744 | Partly covered or sparse source |
| Jun 2023 | 0 | 0 | 720 | Partly covered or sparse source |
| Jul 2023 | 0 | 0 | 744 | Partly covered or sparse source |
| Aug 2023 | 0 | 0 | 744 | Partly covered or sparse source |
| Sep 2023 | 0 | 0 | 720 | Partly covered or sparse source |
| Oct 2023 | 0 | 0 | 744 | Partly covered or sparse source |
| Nov 2023 | 0 | 0 | 720 | Partly covered or sparse source |
| Dec 2023 | 0 | 0 | 744 | Partly covered or sparse source |
| Jan 2024 | 0 | 0 | 744 | Partly covered or sparse source |
| Feb 2024 | 0 | 0 | 696 | Partly covered or sparse source |
| Mar 2024 | 0 | 0 | 744 | Partly covered or sparse source |
| Apr 2024 | 0 | 0 | 720 | Partly covered or sparse source |
| May 2024 | 0 | 0 | 744 | Partly covered or sparse source |
| Jun 2024 | 0 | 0 | 720 | Partly covered or sparse source |
| Jul 2024 | 0 | 0 | 744 | Partly covered or sparse source |
| Aug 2024 | 0 | 0 | 744 | Partly covered or sparse source |
| Sep 2024 | 0 | 0 | 720 | Partly covered or sparse source |
| Oct 2024 | 0 | 0 | 744 | Partly covered or sparse source |
| Nov 2024 | 0 | 0 | 720 | Partly covered or sparse source |
| Dec 2024 | 0 | 0 | 744 | Partly covered or sparse source |
| Jan 2025 | 0 | 0 | 744 | Partly covered or sparse source |
| Feb 2025 | 0 | 0 | 672 | Partly covered or sparse source |
| Mar 2025 | 0 | 0 | 744 | Partly covered or sparse source |
| Apr 2025 | 0 | 0 | 720 | Partly covered or sparse source |
| May 2025 | 0 | 0 | 744 | Partly covered or sparse source |
| Jun 2025 | 0 | 0 | 720 | Partly covered or sparse source |
| Jul 2025 | 0 | 0 | 744 | Partly covered or sparse source |
| Aug 2025 | 0 | 0 | 744 | Partly covered or sparse source |
| Sep 2025 | 0 | 0 | 720 | Partly covered or sparse source |
| Oct 2025 | 0 | 0 | 744 | Partly covered or sparse source |
| Nov 2025 | 0 | 0 | 720 | Partly covered or sparse source |
| Dec 2025 | 29 | 29 | 744 | Partly covered or sparse source |
| Jan 2026 | 44 | 44 | 744 | Partly covered or sparse source |
| Feb 2026 | 0 | 0 | 672 | Partly covered or sparse source |
| Mar 2026 | 0 | 0 | 744 | Partly covered or sparse source |
| Apr 2026 | 0 | 0 | 720 | Partly covered or sparse source |
| May 2026 | 0 | 0 | 744 | Partly covered or sparse source |
| Jun 2026 | 0 | 0 | 720 | Partly covered or sparse source |
| Jul 2026 | 0 | 0 | 744 | Partly covered or sparse source |
| Aug 2026 | 0 | 0 | 744 | Partly covered or sparse source |
| Sep 2026 | 0 | 0 | 720 | Partly covered or sparse source |
| Oct 2026 | 0 | 0 | 744 | Partly covered or sparse source |
| Nov 2026 | 0 | 0 | 32 | Partly covered or sparse source |
Days with a discharge per month
A day counts when any counted discharge was under way on it (start to reported end, local time); an event with no end counts its start day.
- No source
- Partly covered or sparse source
No source covers 2022-01 to 2022-04.
Source: EPA ECHO sewer overflow events. Covered 2022-05-03 to 2026-11-02.
Show table
| Month | Days with a discharge | Coverage |
|---|---|---|
| Jan 2022 | 0 | No source |
| Feb 2022 | 0 | No source |
| Mar 2022 | 0 | No source |
| Apr 2022 | 0 | No source |
| May 2022 | 0 | Partly covered or sparse source |
| Jun 2022 | 0 | Partly covered or sparse source |
| Jul 2022 | 0 | Partly covered or sparse source |
| Aug 2022 | 0 | Partly covered or sparse source |
| Sep 2022 | 0 | Partly covered or sparse source |
| Oct 2022 | 0 | Partly covered or sparse source |
| Nov 2022 | 0 | Partly covered or sparse source |
| Dec 2022 | 0 | Partly covered or sparse source |
| Jan 2023 | 0 | Partly covered or sparse source |
| Feb 2023 | 0 | Partly covered or sparse source |
| Mar 2023 | 0 | Partly covered or sparse source |
| Apr 2023 | 0 | Partly covered or sparse source |
| May 2023 | 0 | Partly covered or sparse source |
| Jun 2023 | 0 | Partly covered or sparse source |
| Jul 2023 | 0 | Partly covered or sparse source |
| Aug 2023 | 0 | Partly covered or sparse source |
| Sep 2023 | 0 | Partly covered or sparse source |
| Oct 2023 | 0 | Partly covered or sparse source |
| Nov 2023 | 0 | Partly covered or sparse source |
| Dec 2023 | 0 | Partly covered or sparse source |
| Jan 2024 | 0 | Partly covered or sparse source |
| Feb 2024 | 0 | Partly covered or sparse source |
| Mar 2024 | 0 | Partly covered or sparse source |
| Apr 2024 | 0 | Partly covered or sparse source |
| May 2024 | 0 | Partly covered or sparse source |
| Jun 2024 | 0 | Partly covered or sparse source |
| Jul 2024 | 0 | Partly covered or sparse source |
| Aug 2024 | 0 | Partly covered or sparse source |
| Sep 2024 | 0 | Partly covered or sparse source |
| Oct 2024 | 0 | Partly covered or sparse source |
| Nov 2024 | 0 | Partly covered or sparse source |
| Dec 2024 | 0 | Partly covered or sparse source |
| Jan 2025 | 0 | Partly covered or sparse source |
| Feb 2025 | 0 | Partly covered or sparse source |
| Mar 2025 | 0 | Partly covered or sparse source |
| Apr 2025 | 0 | Partly covered or sparse source |
| May 2025 | 0 | Partly covered or sparse source |
| Jun 2025 | 0 | Partly covered or sparse source |
| Jul 2025 | 0 | Partly covered or sparse source |
| Aug 2025 | 0 | Partly covered or sparse source |
| Sep 2025 | 0 | Partly covered or sparse source |
| Oct 2025 | 0 | Partly covered or sparse source |
| Nov 2025 | 0 | Partly covered or sparse source |
| Dec 2025 | 1 | Partly covered or sparse source |
| Jan 2026 | 0 | Partly covered or sparse source |
| Feb 2026 | 0 | Partly covered or sparse source |
| Mar 2026 | 0 | Partly covered or sparse source |
| Apr 2026 | 0 | Partly covered or sparse source |
| May 2026 | 0 | Partly covered or sparse source |
| Jun 2026 | 0 | Partly covered or sparse source |
| Jul 2026 | 0 | Partly covered or sparse source |
| Aug 2026 | 0 | Partly covered or sparse source |
| Sep 2026 | 0 | Partly covered or sparse source |
| Oct 2026 | 0 | Partly covered or sparse source |
| Nov 2026 | 0 | Partly covered or sparse source |
Reported volume per year
Gallons, summed from the 1 events that gave a number.
- Partly covered or sparse source
Source: EPA ECHO sewer overflow events. Covered 2022-05-03 to 2026-11-02.
Show table
| Year | Gallons | Events with a number | Events without | Coverage |
|---|---|---|---|---|
| 2022 | 0 | 0 | 0 | Partly covered or sparse source |
| 2023 | 0 | 0 | 0 | Partly covered or sparse source |
| 2024 | 0 | 0 | 0 | Partly covered or sparse source |
| 2025 | 10 | 1 | 0 | Partly covered or sparse source |
| 2026 | 0 | 0 | 0 | Partly covered or sparse source |
Hours under advisory per year
Hours under advisory each year; 2026 to date.
- Advisory in effect
- Partly covered or sparse source
Official beach and cyanobacteria advisories are counted on water pages only.
Source: EPA ECHO sewer overflow events. Covered 2022-05-03 to 2026-11-02.
Show table
| Year | Hours under advisory | Share of the year | Coverage |
|---|---|---|---|
| 2022 | 0 | 0.0% | Partly covered or sparse source |
| 2023 | 0 | 0.0% | Partly covered or sparse source |
| 2024 | 0 | 0.0% | Partly covered or sparse source |
| 2025 | 29 | 0.3% | Partly covered or sparse source |
| 2026 | 44 | 0.6% | Partly covered or sparse source |
Discharge events by calendar month, all years
Every counted discharge event, by the calendar month it began.
Months are summed over every year a source covers; the table gives the number of years behind each month.
Source: EPA ECHO sewer overflow events. Covered 2022-05-03 to 2026-11-02.
Show table
| Month | Events | Years of records |
|---|---|---|
| Jan | 0 | 0 |
| Feb | 0 | 0 |
| Mar | 0 | 0 |
| Apr | 0 | 0 |
| May | 0 | 0 |
| Jun | 0 | 0 |
| Jul | 0 | 0 |
| Aug | 0 | 0 |
| Sep | 0 | 0 |
| Oct | 0 | 0 |
| Nov | 0 | 0 |
| Dec | 1 | 0 |
Reported monthly totals: NH permittee notices (Nashua, Manchester, Portsmouth, Exeter)
Portsmouth publishes monthly CSO volumes per outfall, not events. Source: NH permittee notices (Nashua, Manchester, Portsmouth, Exeter). Covered 2010-01-01 to 2025-05-01.
Reported volume
Gallons per year (monthly figures summed by year).
Show table
| Year | Reported volume |
|---|---|
| 2010 | 108,495,900 gal |
| 2011 | 13,681,800 gal |
| 2012 | 10,181,000 gal |
| 2013 | 3,892,600 gal |
| 2014 | 14,709,200 gal |
| 2015 | 3,513,670 gal |
| 2016 | 3,493,200 gal |
| 2017 | 1,229,800 gal |
| 2018 | 7,808,300 gal |
| 2019 | 3,542,000 gal |
| 2020 | 916,000 gal |
| 2021 | 1,940,000 gal |
| 2022 | 636,000 gal |
| 2023 | 13,266,000 gal |
| 2024 | 10,248,000 gal |
| 2025 | 55,000 gal |
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.
- EPA ECHO sewer overflow events: 2022-05-03 to now (sparse)