DirtyWaterWatch

Connecticut / Dischargers /

City of Derby WPCF

SSO · Connecticut · Derby

NPDES permit
CT0100161
Outfalls
none with coordinates yet
Receiving waters
Housatonic River; Naugatuck River (confluence)
Tracked waters
Housatonic River, CT, Upper Ansonia Reservoir, CT
Events tracked
65 discharges · latest May 19, 2026, 7:00 AM EDT
Volume reported
6,680,505 gallons across the 33 discharges that give a volume (32 without one)

Source: discharger record from the project's research and EPA ECHO (dischargers.json); counts from the 65 event records below, as of 2026-11-02 11:56 UTC.

How it tells the public

CT DEEP Performance Dashboard (QScend QAlert reports shown in Zoho Analytics open views: https://deepct.qscend.mygovcenter.com/cms/cms?id=1); X/Twitter @CTSewageSpills (manual DEEP posts). Statutory local notice: operator must notify the chief elected official and local health official within 2 h; they must inform the public within 2 h of receipt (CGS 22a-424a(c)(3)) - channel varies by town.

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.

Event history

Events reported for City of Derby WPCF, newest first
StartEnd Water OutfallTypeVolumeSourceLinks
May 19, 2026, 7:00 AM EDT May 20, 2026, 5:00 PM EDT Housatonic River, CT Sewer Main, CT-8, Derby, CT Sanitary sewer overflow “TBD” DERBY (CT DEEP Performance Dashboard) via CT DEEP CSO/SSO Performance Dashboard (QScend), record 10679, the source gives no report time, retrieved 2026-11-02 11:20 UTC · notice Event: Sanitary sewer overflow, DERBY, May 19, 2026, 7:00 AM EDT · Map
May 19, 2026, 12:00 AM EDT ended, time not reported Housatonic River, CT Sewer Main, 1 Caroline St, Derby, CT Sanitary sewer overflow “5 gallons per hour, 11:05 flow has increased to about 10 gallons a minute” DERBY (CT DEEP Performance Dashboard) via CT DEEP CSO/SSO Performance Dashboard (QScend), record 10665, the source gives no report time, retrieved 2026-11-02 11:20 UTC · notice Event: Sanitary sewer overflow, DERBY, May 19, 2026, 12:00 AM EDT · Map
Feb 11, 2026, 12:00 AM EST Feb 11, 2026, 11:00 AM EST Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 1.1 million gal DERBY (CT DEEP Performance Dashboard) via CT DEEP CSO/SSO Performance Dashboard (QScend), record 10314, the source gives no report time, retrieved 2026-11-02 11:20 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Sep 8, 2025, 4:45 AM EDT Sep 8, 2025, 5:45 AM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypassrevised 583,000 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2026) via ct-deep-annual, record 9895-2, published Feb 25, 2026, 4:08 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Sep 8, 2025, 4:45 AM EDT Sep 8, 2025, 5:45 AM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypassrevised 583,000 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2026) via ct-deep-annual, record 9895, published Feb 25, 2026, 4:08 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Sep 8, 2025, 4:45 AM EDT Sep 8, 2025, 5:45 AM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 583,000 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2026) via ct-deep-annual, record 9891, published Feb 25, 2026, 4:08 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Sep 8, 2025, 4:45 AM EDT Sep 8, 2025, 5:45 AM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 583,000 gal DERBY (CT DEEP Performance Dashboard) via CT DEEP CSO/SSO Performance Dashboard (QScend), record 9895, the source gives no report time, retrieved 2026-11-02 11:20 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Jun 9, 2025, 12:00 AM EDT Jun 9, 2025, 5:30 AM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypassrevised 2.25 million gal DERBY (CT DEEP Sewage Right-to-Know annual report 2026) via ct-deep-annual, record 9635-2, published Feb 25, 2026, 4:08 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Jun 9, 2025, 12:00 AM EDT Jun 9, 2025, 5:30 AM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypassrevised 2.25 million gal DERBY (CT DEEP Sewage Right-to-Know annual report 2026) via ct-deep-annual, record 9635, published Feb 25, 2026, 4:08 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Jun 9, 2025, 12:00 AM EDT Jun 9, 2025, 5:30 AM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 2.25 million gal DERBY (CT DEEP Performance Dashboard) via CT DEEP CSO/SSO Performance Dashboard (QScend), record 9635, the source gives no report time, retrieved 2026-11-02 11:20 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Apr 21, 2025, 10:00 AM EDT Apr 21, 2025, 10:15 AM EDT not placed Manhole, 210 Emmett Ave, Derby, CT Sanitary sewer overflowrevised 30 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2026) via ct-deep-annual, record 9397-2, published Feb 25, 2026, 4:08 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below
Full record (older than 180 days, so no page of its own)

This record in the archive list
Apr 21, 2025, 10:00 AM EDT Apr 21, 2025, 10:15 AM EDT not placed Manhole, 210 Emmett Ave, Derby, CT Sanitary sewer overflowrevised 30 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2026) via ct-deep-annual, record 9397, published Feb 25, 2026, 4:08 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below
Full record (older than 180 days, so no page of its own)

This record in the archive list
Apr 21, 2025, 10:00 AM EDT Apr 21, 2025, 10:15 AM EDT not placed Manhole, 210 Emmett Ave, Derby, CT Sanitary sewer overflow 30 gal DERBY (CT DEEP Performance Dashboard) via CT DEEP CSO/SSO Performance Dashboard (QScend), record 9397, the source gives no report time, retrieved 2026-11-02 11:20 UTC · notice record below
Full record (older than 180 days, so no page of its own)

This record in the archive list
Aug 18, 2024, 11:30 PM EDT Aug 19, 2024, 12:00 AM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 70,000 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2025) via ct-deep-annual, record x5345c72bae57, published Mar 31, 2025, 1:52 PM EDT, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

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Aug 15, 2024, 11:30 AM EDT Aug 15, 2024, 1:00 PM EDT not placed Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 90 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2025) via ct-deep-annual, record x4d18ee25a798, published Mar 31, 2025, 1:52 PM EDT, retrieved 2026-11-02 11:53 UTC · notice record below
Full record (older than 180 days, so no page of its own)

This record in the archive list
May 1, 2024, 4:45 AM EDT May 1, 2024, 5:15 AM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 40,000 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2025) via ct-deep-annual, record x49d1404ea1a3, published Mar 31, 2025, 1:52 PM EDT, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Dec 18, 2023, 8:00 AM EST Dec 19, 2023, 12:00 AM EST Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 1.5 million gal DERBY (CT DEEP Sewage Right-to-Know annual report 2024) via ct-deep-annual, record xa066ac1ee145, published Jan 9, 2025, 2:55 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

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Nov 24, 2023, 3:00 AM EST Nov 24, 2023, 12:00 PM EST not placed Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 23,000 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2024) via ct-deep-annual, record xc8dd6009c4eb, published Jan 9, 2025, 2:55 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below
Full record (older than 180 days, so no page of its own)

This record in the archive list
Jul 4, 2023, 5:00 PM EDT Jul 4, 2023, 8:30 PM EDT Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 85,000 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2024) via ct-deep-annual, record x3b863cfd1856, published Jan 9, 2025, 2:55 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

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Jan 26, 2023, 4:30 AM EST Jan 26, 2023, 8:15 AM EST Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 200,000 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2024) via ct-deep-annual, record x7fea07d8d7d7-2, published Jan 9, 2025, 2:55 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Jan 26, 2023, 4:30 AM EST Jan 26, 2023, 8:15 AM EST Housatonic River, CT Treatment Plant, 1 Caroline St, Derby, CT Treatment plant bypass 200,000 gal DERBY (CT DEEP Sewage Right-to-Know annual report 2024) via ct-deep-annual, record x7fea07d8d7d7, published Jan 9, 2025, 2:55 PM EST, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

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Oct 10, 2021, 10:15 AM EDT Oct 10, 2021, 12:01 PM EDT Housatonic River, CT Lateral - Private, 19 Cherry st Sanitary sewer overflow “Undetermined” Derby (CT DEEP Sewage Right-to-Know annual report 2022) via ct-deep-annual, record x5190d050279f-2, published Oct 9, 2024, 12:47 PM EDT, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

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Oct 10, 2021, 10:15 AM EDT Oct 10, 2021, 12:01 PM EDT Housatonic River, CT Lateral - Private, 19 Cherry st Sanitary sewer overflow 0 gal Derby (CT DEEP Sewage Right-to-Know annual report 2022) via ct-deep-annual, record x5190d050279f, published Oct 9, 2024, 12:47 PM EDT, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Oct 10, 2021, 10:15 AM EDT Oct 10, 2021, 12:01 PM EDT Housatonic River, CT Lateral - Private, 19 Cherry st Sanitary sewer overflow “Undetermined” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965441, reported Oct 10, 2021, 12:13 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)

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Sep 2, 2021, 4:30 AM EDT Sep 2, 2021, 6:20 AM EDT not placed Treatment Plant, Caroline St Treatment plant bypass 10,000 gal Derby (CT DEEP Sewage Right-to-Know annual report 2022) via ct-deep-annual, record x9ce0d50aebf6, published Oct 9, 2024, 12:47 PM EDT, retrieved 2026-11-02 11:53 UTC · notice record below
Full record (older than 180 days, so no page of its own)

This record in the archive list
Sep 2, 2021, 4:30 AM EDT Sep 2, 2021, 6:20 AM EDT Housatonic River, CT Treatment Plant, Caroline St Treatment plant bypass “5,001 - 20,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963962, reported Sep 2, 2021, 6:31 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Aug 23, 2021, 10:30 AM EDT Aug 23, 2021, 12:19 PM EDT not placed Treatment Plant, Factory st Treatment plant bypass 3,000 gal Derby (CT DEEP Sewage Right-to-Know annual report 2022) via ct-deep-annual, record xff13cde4e54f, published Oct 9, 2024, 12:47 PM EDT, retrieved 2026-11-02 11:53 UTC · notice record below
Full record (older than 180 days, so no page of its own)

This record in the archive list
Aug 23, 2021, 10:30 AM EDT Aug 23, 2021, 12:19 PM EDT Housatonic River, CT Treatment Plant, Factory st Treatment plant bypass “1,001 - 5,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963627, reported Aug 23, 2021, 12:24 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)

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Jul 9, 2021, 9:00 AM EDT Jul 9, 2021, 9:00 AM EDT Housatonic River, CT Treatment Plant, 1 caroline street derby ct Treatment plant bypass 3,000 gal Derby (CT DEEP Sewage Right-to-Know annual report 2022) via ct-deep-annual, record x0eb279248506, published Oct 9, 2024, 12:47 PM EDT, retrieved 2026-11-02 11:53 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Jul 9, 2021, 9:00 AM EDT not reported Housatonic River, CT Treatment Plant, 1 caroline street derby ct Treatment plant bypass “Undetermined” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964002, reported Jul 9, 2021, 10:36 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Mar 16, 2021, 12:36 PM EDT Mar 22, 2021, 10:00 AM EDT not placed Lateral - Private, 8th street Derby, ct 06418 Sanitary sewer overflow 30 gal Derby (CT DEEP Sewage Right-to-Know annual report 2022) via ct-deep-annual, record xb1345d32a077, published Oct 9, 2024, 12:47 PM EDT, retrieved 2026-11-02 11:53 UTC · notice record below
Full record (older than 180 days, so no page of its own)

This record in the archive list
Mar 16, 2021, 12:36 PM EDT Mar 22, 2021, 10:00 AM EDT not placed Lateral - Private, 8th street Derby, ct 06418 Sanitary sewer overflow “1 - 50” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965685, reported Mar 16, 2021, 1:01 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)

This record in the archive list
Mar 16, 2021, 12:36 PM EDT not reported not placed Lateral - Private, 8th street Derby, ct 06418 Sanitary sewer overflow “1 - 50” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965684, reported Mar 16, 2021, 1:01 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)

This record in the archive list
Sep 13, 2020, 7:45 PM EDT Sep 13, 2020, 8:45 PM EDT not placed Sewer Main, Emmett ave Derby ct Sanitary sewer overflow 5 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964342, reported Sep 13, 2020, 9:25 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)

This record in the archive list
Sep 10, 2020, 6:00 PM EDT Sep 10, 2020, 7:29 PM EDT Housatonic River, CT Treatment Plant, Caroline St Treatment plant bypass “1,001 - 5,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963628, reported Sep 10, 2020, 7:34 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)

This record in the archive list
Jul 3, 2020, 5:00 PM EDT Jul 3, 2020, 6:34 PM EDT Housatonic River, CT Treatment Plant, Hallock ct Treatment plant bypass “501 - 1,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963629, reported Jul 3, 2020, 6:35 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)

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Mar 2, 2020, 8:40 AM EST Jul 9, 2021, 11:30 AM EDT Housatonic River, CT Treatment Plant, Camptown road Treatment plant bypass 100 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964652, reported Mar 2, 2020, 8:44 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Mar 2, 2020, 8:40 AM EST Jul 9, 2021, 12:00 AM EDT Housatonic River, CT Treatment Plant, Camptown road Treatment plant bypass 100 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964595, reported Mar 2, 2020, 8:44 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Mar 2, 2020, 8:40 AM EST not reported Housatonic River, CT Manhole, Camptown road Sanitary sewer overflow 100 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964594, reported Mar 2, 2020, 8:44 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Feb 17, 2020, 6:03 PM EST Feb 17, 2020, 8:05 PM EST Housatonic River, CT Treatment Plant, Caroline st Treatment plant bypass “501 - 1,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964169, reported Feb 17, 2020, 8:09 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)

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Jan 2, 2020, 3:00 PM EST Jan 10, 2020, 2:45 PM EST “Naugatuck river” (not placed) Lateral - Private, Mount Pleasant st Sanitary sewer overflow “1 - 50” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964057, reported Jan 7, 2020, 10:47 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Dec 14, 2019, 6:00 PM EST Dec 20, 2019, 4:00 PM EST Housatonic River, CT Treatment Plant, Caroline st Treatment plant bypass “Undetermined” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964167, reported Dec 14, 2019, 11:11 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)

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Dec 14, 2019, 5:00 PM EST Dec 20, 2019, 4:00 PM EST Housatonic River, CT Treatment Plant, 1 caroline street. cross street Hallock court Treatment plant bypass “Over 1,000,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964029, reported Dec 16, 2019, 7:40 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Dec 14, 2019, 7:39 AM EST Dec 20, 2019, 4:00 PM EST Housatonic River, CT Treatment Plant, Caroline St. Treatment plant bypass “Undetermined” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963631, reported Dec 14, 2019, 7:46 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

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Nov 6, 2019, 1:15 PM EST Nov 6, 2019, 1:59 PM EST Housatonic River, CT Treatment Plant, water st Treatment plant bypass “51 - 500 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964139, reported Nov 6, 2019, 2:05 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)

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Oct 27, 2019, 11:00 AM EDT Oct 27, 2019, 12:00 PM EDT Housatonic River, CT Treatment Plant, 1 caroline street. cross street Hallock court Treatment plant bypass “5,001 - 20,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964003, reported Oct 28, 2019, 7:00 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Oct 16, 2019, 10:45 PM EDT Oct 16, 2019, 11:34 PM EDT Housatonic River, CT Treatment Plant, Factory St Treatment plant bypass “20,001 - 50,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963638, reported Oct 16, 2019, 11:36 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)

This record in the archive list
Oct 1, 2019, 9:00 AM EDT Oct 1, 2019, 1:00 PM EDT Housatonic River, CT Pump Station, Intersection of North ave and route 34 Sanitary sewer overflow 20,000 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964157, reported Oct 1, 2019, 10:20 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Sep 7, 2019, 8:45 PM EDT Sep 7, 2019, 10:45 PM EDT not placed Basement, Ferrara Ct and Indian ave Sanitary sewer overflow “1 - 50” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965215, reported Sep 8, 2019, 8:26 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Jul 11, 2019, 4:00 PM EDT Jul 11, 2019, 7:00 PM EDT not placed Sewer Main, 222 Derby Ave CT Sanitary sewer overflow “51 - 500 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964991, reported Jul 17, 2019, 12:52 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)

This record in the archive list
Feb 7, 2019, 3:00 PM EST Feb 7, 2019, 3:15 PM EST Housatonic River, CT Pump Station, Roosevelt Ave / Cemetery Ave intersection Sanitary sewer overflow “10-20 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963174, reported Feb 7, 2019, 4:11 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)

This record in the archive list
Sep 25, 2018, 7:05 PM EDT Sep 25, 2018, 7:00 PM EDT Housatonic River, CT Treatment Plant, Caroline Street Treatment plant bypass “1,001 - 5,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963990, reported Sep 25, 2018, 9:11 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)

This record in the archive list
Sep 25, 2018, 7:00 PM EDT Sep 25, 2018, 8:57 PM EDT Housatonic River, CT Manhole, Derby Ave Sanitary sewer overflow “1,001 - 5,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963963, reported Sep 25, 2018, 9:05 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)

This record in the archive list
Jun 19, 2018, 1:45 PM EDT Jun 19, 2018, 2:00 PM EDT Housatonic River, CT Treatment Plant, 1 Caroline St Treatment plant bypass “1 - 50” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965545, reported Jun 19, 2018, 2:14 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)

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Jun 5, 2018, 1:00 PM EDT Jun 5, 2018, 2:00 PM EDT Housatonic River, CT Pump Station, North St Sanitary sewer overflow “1,001 - 5,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964156, reported Jun 5, 2018, 2:39 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)

This record in the archive list
May 31, 2018, 6:42 AM EDT May 31, 2018, 6:42 AM EDT Housatonic River, CT Treatment Plant, Caroline st Treatment plant bypass “1 - 50” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965533, reported May 31, 2018, 6:49 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
May 3, 2018, 7:00 AM EDT May 3, 2018, 8:20 AM EDT Housatonic River, CT Treatment Plant, CAROLINE ST Treatment plant bypass “1 - 50” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965440, reported May 3, 2018, 8:22 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
Full record (older than 180 days, so no page of its own)

This record in the archive list
Apr 16, 2018, 12:18 PM EDT Apr 17, 2018, 6:30 AM EDT Housatonic River, CT Treatment Plant, Caroline Street Treatment plant bypass 10,000 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963961, reported Apr 16, 2018, 12:24 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)

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Apr 5, 2018, 7:30 AM EDT Apr 5, 2018, 7:31 AM EDT Housatonic River, CT Treatment Plant, Caroline Street Treatment plant bypass 50 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964129, reported Apr 5, 2018, 8:18 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Jan 30, 2018, 8:00 AM EST Jan 30, 2018, 8:00 AM EST Housatonic River, CT Treatment Plant, Caroline st Treatment plant bypass “1 - 50” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965701, reported Mar 1, 2018, 10:47 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Jan 30, 2018, 8:00 AM EST Jan 30, 2018, 8:00 AM EST Housatonic River, CT Treatment Plant, Caroline st Treatment plant bypass “1 - 50” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965700, reported Jan 30, 2018, 9:30 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Nov 15, 2017, 8:15 AM EST Nov 16, 2017, 9:15 AM EST Housatonic River, CT Sewer Main, Burtville Ave Sanitary sewer overflow “1,001 - 5,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965373, reported Mar 1, 2018, 10:47 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Nov 15, 2017, 8:15 AM EST Nov 16, 2017, 9:15 AM EST Housatonic River, CT Sewer Main, Burtville Ave Sanitary sewer overflow 0 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965372, reported Nov 15, 2017, 9:06 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Oct 24, 2017, 10:46 PM EDT Oct 25, 2017, 5:00 AM EDT Housatonic River, CT Treatment Plant, CAROLINE ST Treatment plant bypass “5,001 - 20,000 gallons” Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963608, reported Mar 1, 2018, 10:47 AM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Oct 24, 2017, 10:46 PM EDT Oct 25, 2017, 5:00 AM EDT Housatonic River, CT Treatment Plant, CAROLINE ST Treatment plant bypass 0 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963607, reported Oct 24, 2017, 10:56 PM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Jul 17, 2017, 9:03 AM EDT Sep 1, 2017, 9:05 AM EDT not placed Pump Station, Division st Sanitary sewer overflow 0 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963048, reported Jul 17, 2017, 9:09 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Jun 13, 2017, 7:51 PM EDT Jun 16, 2017, 2:00 PM EDT Upper Ansonia Reservoir, CT Sewer Main, 105 Academy hill rd. Sanitary sewer overflow 0 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35965532, reported Jun 13, 2017, 8:20 PM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Apr 17, 2017, 6:30 AM EDT Apr 17, 2017, 7:03 AM EDT Housatonic River, CT Treatment Plant, Caroline st Treatment plant bypass 0 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963924, reported Apr 17, 2017, 7:12 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Apr 7, 2017, 12:00 AM EDT Apr 7, 2017, 7:21 AM EDT Housatonic River, CT Treatment Plant, caroline st Treatment plant bypass 0 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35963923, reported Apr 7, 2017, 7:32 AM EDT, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Feb 22, 2017, 5:30 PM EST Feb 22, 2017, 6:45 PM EST not placed Basement, 42 Kings Court Sanitary sewer overflow 0 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35964376, reported Feb 22, 2017, 6:50 PM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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Feb 6, 2017, 12:15 PM EST Feb 10, 2017, 3:00 PM EST not placed Pump Station, 19 South Division Street, Derby Ct 06418 Sanitary sewer overflow 0 gal Derby (CT DEEP reporting archive 2016-2021) via ct-deep-archive, record bypass-35962984, reported Feb 6, 2017, 1:25 PM EST, retrieved 2026-11-02 11:54 UTC · notice record below · Map
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History

  • Discharge events, last 12 months3Dec 2025 to Nov 2026
  • Days with a discharge, last 12 months3Dec 2025 to Nov 2026
  • Hours under advisory, last 12 months141Dec 2025 to Nov 2026; on this discharger's reports
  • 2026 season under advisory1.9%May to October; 82 h

Discharge events per month

14 events, Jan 2022 to Nov 2026. Counted from 9 verified or annual reports, 5 public notices.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Bypass, blended or other

CT DEEP dashboard records begin 2021-12-02; where CT DEEP's annual report covers a discharger's month, the annual report is counted instead. CT DEEP annual reports (Sewage Right-to-Know) cover 2021-01-01 to 2026-11-02.

Sources: CT DEEP CSO/SSO dashboard; CT DEEP Sewage Right-to-Know annual reports. Covered 2022-01-01 to 2026-11-02.

Show table
Discharge events per month
MonthCombined sewer overflowSanitary sewer overflowBypass, blended or otherTotalCounted fromCoverage
Jan 20220000
Feb 20220000
Mar 20220000
Apr 20220000
May 20220000
Jun 20220000
Jul 20220000
Aug 20220000
Sep 20220000
Oct 20220000
Nov 20220000
Dec 20220000
Jan 20230022Verified or annual reports
Feb 20230000
Mar 20230000
Apr 20230000
May 20230000
Jun 20230000
Jul 20230011Verified or annual reports
Aug 20230000
Sep 20230000
Oct 20230000
Nov 20230011Verified or annual reports
Dec 20230011Verified or annual reports
Jan 20240000
Feb 20240000
Mar 20240000
Apr 20240000
May 20240011Verified or annual reports
Jun 20240000
Jul 20240000
Aug 20240022Verified or annual reports
Sep 20240000
Oct 20240000
Nov 20240000
Dec 20240000
Jan 20250000
Feb 20250000
Mar 20250000
Apr 20250101Public notices (no report yet)
May 20250000
Jun 20250011Public notices (no report yet)
Jul 20250000
Aug 20250000
Sep 20250011Verified or annual reports
Oct 20250000
Nov 20250000
Dec 20250000
Jan 20260000
Feb 20260011Public notices (no report yet)
Mar 20260000
Apr 20260000
May 20260202Public notices (no report yet)
Jun 20260000
Jul 20260000
Aug 20260000
Sep 20260000
Oct 20260000
Nov 20260000

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

5 discharge events have no reported end and no ongoing status; under the status rules they set caution, not an advisory, and add no hours here. 3 events reported to last more than 31 days are counted to 31 days. Official beach and cyanobacteria advisories are counted on water pages only. CT DEEP dashboard records begin 2021-12-02; where CT DEEP's annual report covers a discharger's month, the annual report is counted instead. CT DEEP annual reports (Sewage Right-to-Know) cover 2021-01-01 to 2026-11-02. CT DEEP's reporting archive runs 2016-07-04 to 2021-12-02.

Sources: CT DEEP CSO/SSO dashboard; CT DEEP Sewage Right-to-Know annual reports; CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2026-11-02.

Show table
Hours under advisory per month
MonthHours under advisoryFrom discharge windowsHours in monthCoverage
Jan 202200744
Feb 202200672
Mar 202200744
Apr 202200720
May 202200744
Jun 202200720
Jul 202200744
Aug 202200744
Sep 202200720
Oct 202200744
Nov 202200720
Dec 202200744
Jan 20235252744
Feb 202300672
Mar 202300744
Apr 202300720
May 202300744
Jun 202300720
Jul 20235252744
Aug 202300744
Sep 202300720
Oct 202300744
Nov 20235757720
Dec 20236464744
Jan 202400744
Feb 202400696
Mar 202400744
Apr 202400720
May 20244949744
Jun 202400720
Jul 202400744
Aug 20249898744
Sep 202400720
Oct 202400744
Nov 202400720
Dec 202400744
Jan 202500744
Feb 202500672
Mar 202500744
Apr 20254848720
May 202500744
Jun 20255454720
Jul 202500744
Aug 202500744
Sep 20254949720
Oct 202500744
Nov 202500720
Dec 202500744
Jan 202600744
Feb 20265959672
Mar 202600744
Apr 202600720
May 20268282744
Jun 202600720
Jul 202600744
Aug 202600744
Sep 202600720
Oct 202600744
Nov 20260032

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.

Sources: CT DEEP CSO/SSO dashboard; CT DEEP Sewage Right-to-Know annual reports. Covered 2022-01-01 to 2026-11-02.

Show table
Days with a discharge per month
MonthDays with a dischargeCoverage
Jan 20220
Feb 20220
Mar 20220
Apr 20220
May 20220
Jun 20220
Jul 20220
Aug 20220
Sep 20220
Oct 20220
Nov 20220
Dec 20220
Jan 20231
Feb 20230
Mar 20230
Apr 20230
May 20230
Jun 20230
Jul 20231
Aug 20230
Sep 20230
Oct 20230
Nov 20231
Dec 20232
Jan 20240
Feb 20240
Mar 20240
Apr 20240
May 20241
Jun 20240
Jul 20240
Aug 20243
Sep 20240
Oct 20240
Nov 20240
Dec 20240
Jan 20250
Feb 20250
Mar 20250
Apr 20251
May 20250
Jun 20251
Jul 20250
Aug 20250
Sep 20251
Oct 20250
Nov 20250
Dec 20250
Jan 20260
Feb 20261
Mar 20260
Apr 20260
May 20262
Jun 20260
Jul 20260
Aug 20260
Sep 20260
Oct 20260
Nov 20260

Discharge events per year, 2016 to 2026

64 events, 2016 to 2026.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Bypass, blended or other
  • Partly covered or sparse source

CT DEEP dashboard records begin 2021-12-02; where CT DEEP's annual report covers a discharger's month, the annual report is counted instead. CT DEEP annual reports (Sewage Right-to-Know) cover 2021-01-01 to 2026-11-02. CT DEEP's reporting archive runs 2016-07-04 to 2021-12-02.

Sources: CT DEEP CSO/SSO dashboard; CT DEEP Sewage Right-to-Know annual reports; CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2026-11-02.

Show table
Discharge events per year, 2016 to 2026
YearCombined sewer overflowSanitary sewer overflowBypass, blended or otherTotalCoverage
20160000Partly covered or sparse source
201706410
201802810
201904610
20200358
202106612Partly covered or sparse source
20220000
20230055
20240033
20250123
20260213

Reported volume per year

Gallons, summed from the 32 events that gave a number (32 did not).

  • Partly covered or sparse source

32 of 64 events gave no volume as a number (25 gave a range); only numbers are summed. CT DEEP's 2016-2021 archive gives volumes as ranges ("20,001 - 50,000 gallons"); they are not summed.

Sources: CT DEEP CSO/SSO dashboard; CT DEEP Sewage Right-to-Know annual reports; CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2026-11-02.

Show table
Reported volume per year
YearGallonsEvents with a numberEvents withoutCoverage
2016000Partly covered or sparse source
2017082
201810,05028
201920,00019
202030544
202116,03057Partly covered or sparse source
2022000
20232,008,00050
2024110,09030
20252,833,03030
20261,100,00012

Hours under advisory per year

Hours under advisory each year; 2026 to date.

  • Advisory in effect
  • Partly covered or sparse source

5 discharge events have no reported end and no ongoing status; under the status rules they set caution, not an advisory, and add no hours here. 3 events reported to last more than 31 days are counted to 31 days. Official beach and cyanobacteria advisories are counted on water pages only.

Sources: CT DEEP CSO/SSO dashboard; CT DEEP Sewage Right-to-Know annual reports; CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2026-11-02.

Show table
Hours under advisory per year
YearHours under advisoryShare of the yearCoverage
201600.0%Partly covered or sparse source
20171,33315.2%
20184074.6%
20195486.3%
20201,23014.0%
20213874.4%Partly covered or sparse source
202200.0%
20232242.6%
20241471.7%
20251511.7%
20261411.9%

Share of the May to October season under advisory

Share of the hours from May 1 to October 31 with an advisory in effect.

  • Advisory in effect
  • Season partly covered

Seasons only partly covered by a source: 2016 (share is of the covered hours). 5 discharge events have no reported end and no ongoing status; under the status rules they set caution, not an advisory, and add no hours here. 3 events reported to last more than 31 days are counted to 31 days. Official beach and cyanobacteria advisories are counted on water pages only.

Sources: CT DEEP CSO/SSO dashboard; CT DEEP Sewage Right-to-Know annual reports; CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2026-11-02.

Show table
Share of the May to October season under advisory
SeasonShare under advisoryHours under advisoryHours coveredSeason hoursPartly covered
20160.0%02,8764,416yes
201721.8%9604,4164,416
20185.5%2454,4164,416
20195.7%2514,4164,416
20203.4%1484,4164,416
20214.5%1974,4164,416
20220.0%04,4164,416
20231.2%524,4164,416
20243.3%1474,4164,416
20252.3%1034,4164,416
20261.9%824,4164,416

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.

Sources: CT DEEP CSO/SSO dashboard; CT DEEP Sewage Right-to-Know annual reports; CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2026-11-02.

Show table
Discharge events by calendar month, all years
MonthEventsYears of records
Jan510
Feb510
Mar610
Apr510
May510
Jun410
Jul611
Aug411
Sep811
Oct811
Nov411
Dec410

Discharge events by outfall

The 10 outfalls with the most events of 30, all years.

CT DEEP dashboard records begin 2021-12-02; where CT DEEP's annual report covers a discharger's month, the annual report is counted instead. CT DEEP annual reports (Sewage Right-to-Know) cover 2021-01-01 to 2026-11-02. CT DEEP's reporting archive runs 2016-07-04 to 2021-12-02.

Sources: CT DEEP CSO/SSO dashboard; CT DEEP Sewage Right-to-Know annual reports; CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2026-11-02.

Show table
Discharge events by outfall
OutfallDischargerEvents
Treatment Plant, Caroline StDerby13
Treatment Plant, 1 Caroline St, Derby, CTDERBY11
Lateral - Private, 19 Cherry stDerby3
Treatment Plant, Factory stDerby3
Lateral - Private, 8th street Derby, ct 06418Derby3
Treatment Plant, Caroline StreetDerby3
Treatment Plant, 1 caroline street derby ctDerby2
Treatment Plant, Camptown roadDerby2
Treatment Plant, 1 caroline street. cross street Hallock courtDerby2
Sewer Main, Burtville AveDerby2
Other outfalls (20)20
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.

  • CT DEEP CSO/SSO dashboard: 2021-12-02 to now
  • CT DEEP Sewage Right-to-Know annual reports: 2021-01-01 to now
  • CT DEEP reporting archive 2016-2021: 2016-07-04 to 2021-12-02