DirtyWaterWatch

Connecticut / Waters /

Upper Ansonia Reservoir

Reservoir in Connecticut · near Shelton

Status now

No current report

At least one source we follow covers this water, and nothing it reports applies right now.

Why this colour: No current report: nothing a covering source reports colours this water now. How long a water stays coloured, and why

Source: ct-deep-archive, last answered 2026-11-02 11:54 UTC. Status computed by DirtyWaterWatch as of 2026-11-02 11:56 UTC.

It is not a finding about the water. Discharges go unreported, reports arrive late, and storm runoff carries bacteria too. Follow posted signs and local health advice.

As of Nov 2, 2026, 6:56 AM EST.

Map

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.

Outfalls are small brown dots.

The last 90 days

Last 90 days, hour by hour. Red: advisory in effect; yellow: caution; hatched yellow: unresolved, no end reported; grey: no current report; hatched purple: a source was not updating.

No red or yellow period in this span.

Source: hourly statuses computed by DirtyWaterWatch (pipeline build/status.py) from the events linked above and the rules on the methods page; history as of 2026-11-02 11:56 UTC.

Discharges over the years

  • Discharge events, last 12 months0Dec 2025 to Nov 2026; partly covered or sparse source
  • Hours under advisory, last 12 months0Dec 2025 to Nov 2026; partly covered or sparse source
  • 2021 season under advisory0.0%May to October; 0 h

Discharge events per month

0 events, Jan 2022 to Nov 2026.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Bypass, blended or other
  • No source
No sourceNo source

No source covers 2022-01 to 2026-11.

Source: CT DEEP reporting archive 2016-2021. Covered 2022-01-01 to 2021-12-02.

Show table
Discharge events per month
MonthCombined sewer overflowSanitary sewer overflowBypass, blended or otherTotalCounted fromCoverage
Jan 20220000No source
Feb 20220000No source
Mar 20220000No source
Apr 20220000No source
May 20220000No source
Jun 20220000No source
Jul 20220000No source
Aug 20220000No source
Sep 20220000No source
Oct 20220000No source
Nov 20220000No source
Dec 20220000No source
Jan 20230000No source
Feb 20230000No source
Mar 20230000No source
Apr 20230000No source
May 20230000No source
Jun 20230000No source
Jul 20230000No source
Aug 20230000No source
Sep 20230000No source
Oct 20230000No source
Nov 20230000No source
Dec 20230000No source
Jan 20240000No source
Feb 20240000No source
Mar 20240000No source
Apr 20240000No source
May 20240000No source
Jun 20240000No source
Jul 20240000No source
Aug 20240000No source
Sep 20240000No source
Oct 20240000No source
Nov 20240000No source
Dec 20240000No source
Jan 20250000No source
Feb 20250000No source
Mar 20250000No source
Apr 20250000No source
May 20250000No source
Jun 20250000No source
Jul 20250000No source
Aug 20250000No source
Sep 20250000No source
Oct 20250000No source
Nov 20250000No source
Dec 20250000No source
Jan 20260000No source
Feb 20260000No source
Mar 20260000No source
Apr 20260000No source
May 20260000No source
Jun 20260000No source
Jul 20260000No source
Aug 20260000No source
Sep 20260000No source
Oct 20260000No source
Nov 20260000No source

Hours under advisory per month

Hours this water was under an advisory, by the map's red rules.

  • Advisory in effect
  • No source
No sourceNo source

No source covers 2022-01 to 2026-11. CT DEEP's reporting archive runs 2016-07-04 to 2021-12-02.

Source: CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2021-12-02.

Show table
Hours under advisory per month
MonthHours under advisoryFrom discharge windowsHours in monthCoverage
Jan 202200744No source
Feb 202200672No source
Mar 202200744No source
Apr 202200720No source
May 202200744No source
Jun 202200720No source
Jul 202200744No source
Aug 202200744No source
Sep 202200720No source
Oct 202200744No source
Nov 202200720No source
Dec 202200744No source
Jan 202300744No source
Feb 202300672No source
Mar 202300744No source
Apr 202300720No source
May 202300744No source
Jun 202300720No source
Jul 202300744No source
Aug 202300744No source
Sep 202300720No source
Oct 202300744No source
Nov 202300720No source
Dec 202300744No source
Jan 202400744No source
Feb 202400696No source
Mar 202400744No source
Apr 202400720No source
May 202400744No source
Jun 202400720No source
Jul 202400744No source
Aug 202400744No source
Sep 202400720No source
Oct 202400744No source
Nov 202400720No source
Dec 202400744No source
Jan 202500744No source
Feb 202500672No source
Mar 202500744No source
Apr 202500720No source
May 202500744No source
Jun 202500720No source
Jul 202500744No source
Aug 202500744No source
Sep 202500720No source
Oct 202500744No source
Nov 202500720No source
Dec 202500744No source
Jan 202600744No source
Feb 202600672No source
Mar 202600744No source
Apr 202600720No source
May 202600744No source
Jun 202600720No source
Jul 202600744No source
Aug 202600744No source
Sep 202600720No source
Oct 202600744No source
Nov 20260032No source

Discharge events per year, 2016 to 2026

1 events, 2016 to 2026.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Bypass, blended or other
  • No source
  • Partly covered or sparse source
No sourceNo source

No source covers 2022 to 2026. CT DEEP's reporting archive runs 2016-07-04 to 2021-12-02.

Source: CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2021-12-02.

Show table
Discharge events per year, 2016 to 2026
YearCombined sewer overflowSanitary sewer overflowBypass, blended or otherTotalCoverage
20160000Partly covered or sparse source
20170101
20180000
20190000
20200000
20210000Partly covered or sparse source
20220000No source
20230000No source
20240000No source
20250000No source
20260000No source

Reported volume per year

Gallons, summed from the 1 events that gave a number.

  • No source
  • Partly covered or sparse source
No sourceNo source

No source covers 2022 to 2026.

Source: CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2021-12-02.

Show table
Reported volume per year
YearGallonsEvents with a numberEvents withoutCoverage
2016000Partly covered or sparse source
2017010
2018000
2019000
2020000
2021000Partly covered or sparse source
2022000No source
2023000No source
2024000No source
2025000No source
2026000No source

Hours under advisory per year

Hours under advisory each year; 2026 to date.

  • Advisory in effect
  • No source
  • Partly covered or sparse source
No sourceNo source

No source covers 2022 to 2026.

Source: CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2021-12-02.

Show table
Hours under advisory per year
YearHours under advisoryShare of the yearCoverage
201600.0%Partly covered or sparse source
20171141.3%
201800.0%
201900.0%
202000.0%
202100.0%Partly covered or sparse source
202200.0%No source
202300.0%No source
202400.0%No source
202500.0%No source
202600.0%No source

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).

Source: CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2021-12-02.

Show table
Share of the May to October season under advisory
SeasonShare under advisoryHours under advisoryHours coveredSeason hoursPartly covered
20160.0%02,8764,416yes
20172.6%1144,4164,416
20180.0%04,4164,416
20190.0%04,4164,416
20200.0%04,4164,416
20210.0%04,4164,416

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.

Source: CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2021-12-02.

Show table
Discharge events by calendar month, all years
MonthEventsYears of records
Jan05
Feb05
Mar05
Apr05
May05
Jun15
Jul06
Aug06
Sep06
Oct06
Nov06
Dec06

Discharge events by outfall

The 1 outfalls with the most events of 1, all years.

CT DEEP's reporting archive runs 2016-07-04 to 2021-12-02.

Source: CT DEEP reporting archive 2016-2021. Covered 2016-07-04 to 2021-12-02.

Show table
Discharge events by outfall
OutfallEvents
Sewer Main, 105 Academy hill rd.1
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 reporting archive 2016-2021: 2016-07-04 to 2021-12-02

Every event on Upper Ansonia Reservoir

Events placed on Upper Ansonia Reservoir, newest first
StartEnd Discharger OutfallTypeVolumeSourceLinks
Jun 13, 2017, 7:51 PM EDT Jun 16, 2017, 2:00 PM EDT Derby 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
Full record (older than 180 days, so no page of its own)

This record in the archive list

Outfalls on this water

No outfall in the registry is matched to this water.

Dischargers: City of Derby WPCF.

Launches

Source: OpenBoatLaunch launch records (public agency data and OpenStreetMap, ODbL). · Upper Ansonia Reservoir on OpenBoatLaunch

Sources covering this water

1 event placed on this water in this build.