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Michigan / Waters /

Cass River

River in Michigan, past Caro, Frankenmuth and Saginaw

Current status

No current status shown

No current status is assigned to this water outline. Check the water page for reports and any estimated downstream stretches. Why this status, and its source

Map sources: water outlines and launches from OpenBoatLaunch and OpenStreetMap contributors (Open Database License); wastewater outlets from EPA and state records; downstream estimates by DirtyWaterWatch using U.S. Geological Survey maps and flow data. Base map: OpenFreeMap and OpenMapTiles.

Square boat markers mark boat launches listed by OpenBoatLaunch.

Check Bridgeport Charter Township's notices · Bookmark this water page and check it before each trip · Report a missing notice or error

About this status

No current status shown: no report we track sets a status on this water now; how statuses work. No status does not mean the water is safe. Follow posted signs and local health advice.

Sources checked: a public source (last successful check 2026-11-05 01:05 UTC); a public source (last successful check 2026-11-05 01:05 UTC); EGLE MiEnviro CSO/SSO List (last successful check 2026-11-05 01:08 UTC). Status by DirtyWaterWatch, updated 2026-11-05 01:25 UTC. · Updated

The last 90 days

Last 90 days, hour by hour. Red: discharge or advisory reported. Amber: caution. Hatched amber: end not confirmed. Plum: algal bloom advisory. Red or amber with a light line inside: beach advisory or caution. Dotted: monthly report (days with discharge, dates not given). Grey: no current status on the water outline. Purple hatching: source update overdue.

No discharge, advisory or caution periods are shown for this water in this time span. Check downstream stretches and source coverage.

Source: DirtyWaterWatch calculations using the reports named above and the published status rules. Updated 2026-11-05 01:25 UTC.

Reported discharges over time

  • Discharges affecting the Cass River in Michigan, last 12 months66 affecting this stretch: 6 reported on the Cass River; none arriving from upstreamDecember 2025 to November 2026Verified reports where available, else notices; revisions and duplicates counted once. Arriving discharges are estimated from modeled downstream reaches.
  • Days with a discharge affecting the Cass River in Michigan, last 12 months2Reported on the Cass River in Michigan: 2 · Arriving from outfalls upstream, estimated: 0 (counted apart; together they need not equal the total)December 2025 to November 2026A day counts once however many discharges were under way on it.
  • Hours with a discharge or advisory status on the Cass River in Michigan, last 12 months337Reported on the Cass River in Michigan: 337 · Arriving from outfalls upstream, estimated: 0December 2025 to November 2026Red hours by the map's rules: each discharge to its reported end plus the state's post-discharge period; overlapping hours count once.
  • 2026 season with a discharge or advisory status on the Cass River in Michigan0.0%May to October 2026Share of May 1 to October 31 hours with red status by the map's rules, of the hours a source covered.
  • Records behind the last-90-days strip for the Cass River in Michigan0last 90 daysEvery distinct record the strip lists for its red, yellow and unresolved hours, notices and unresolved reports included; counted as the strip counts them.

Combined sewer overflow (CSO): sewage mixed with rainwater spills from a shared sewer system. Sanitary sewer overflow (SSO): sewage spills from a sewer meant to carry sewage separately from rainwater. Treatment bypass: wastewater skips one or more treatment steps. Blended discharge: wastewater that skipped some treatment is mixed with treated wastewater. Outfall: a pipe or outlet where wastewater enters a water body.

Reported discharges per month

10 reported discharges, January 2022 to November 2026.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Treatment bypass, blended or other

Source: mi-egle-mienviro-cso-sso-list. Records cover January 1, 2022 to November 4, 2026.

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Hours with a discharge or advisory status per month

Hours when this water had a discharge or advisory status under DirtyWaterWatch rules.

  • Discharge or advisory reported

Source: mi-egle-mienviro-cso-sso-list. Records cover January 1, 2001 to November 4, 2026.

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Days with a reported discharge per month

A day counts when any counted discharge was under way on it, from its start to its reported end in Eastern Time; a report with no end counts its start day.

Source: mi-egle-mienviro-cso-sso-list. Records cover January 1, 2022 to November 4, 2026.

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Reported discharges per year, 2001 to 2026

35 reported discharges, 2001 to 2026.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Treatment bypass, blended or other

Source: mi-egle-mienviro-cso-sso-list. Records cover January 1, 2001 to November 4, 2026.

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Reported volume per year

Gallons (axis: K thousand, M million), summed from the 31 reports that gave a volume as a number (4 did not).

4 of 35 discharge reports gave no volume as a number; only numbers are summed.

Source: mi-egle-mienviro-cso-sso-list. Records cover January 1, 2001 to November 4, 2026.

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Hours with a discharge or advisory status per year

Hours with a discharge or advisory status each year under DirtyWaterWatch rules; 2026 to date.

  • Discharge or advisory reported

Source: mi-egle-mienviro-cso-sso-list. Records cover January 1, 2001 to November 4, 2026.

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Share of the May to October season with a discharge or advisory status

Share of the hours from May 1 to October 31 with a discharge or advisory status under DirtyWaterWatch rules.

  • Discharge or advisory reported

Source: mi-egle-mienviro-cso-sso-list. Records cover January 1, 2001 to November 4, 2026.

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Reported discharges by calendar month, all years

Every counted discharge report, by the calendar month it began.

Months are summed over every year a tracked source covers; the table gives the number of years behind each month.

Source: mi-egle-mienviro-cso-sso-list. Records cover January 1, 2001 to November 4, 2026.

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Reported discharges by wastewater outlet

Wastewater outlets with the most tracked discharge records: 10 of 22, all years. Counts depend on reporting coverage and do not measure legal compliance or harm.

Source: mi-egle-mienviro-cso-sso-list. Records cover January 1, 2001 to November 4, 2026.

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How these charts are counted

We count each discharge once. Where a source publishes notices and confirmed reports, we use confirmed reports for an operator's month when available; otherwise we use notices. We combine revisions and exclude duplicate state reports copied by the U.S. Environmental Protection Agency (EPA). Monthly and yearly totals appear separately. Status hours follow this site's rules. Shaded gaps mean missing coverage, not zero discharges.

  • U.S. Environmental Protection Agency sewer overflow records: records from May 3, 2022 to the latest update (limited records)
  • mi-egle-mienviro-cso-sso-list: records from January 1, 2001 to the latest update

Reports linked to Cass River

Reports linked to Cass River, newest first
WhenReportStatus
to 12:30 PMCITY OF FRANKENMUTH · Due to high flows the grit chamber overflowed onto the ground and into the stormwater catch basin. · SSO (earlier version) · 200,000 gallons in all mapended
CITY OF FRANKENMUTH · CSO overflow station designed to overflow sanitary sewer flow into the stormwater line. · SSO · volume in each report mapongoing
Tuscola County Board of Public Works · Cass River via WWTP discharge pipe after disinfection contact chamber · Bypass · volume not reported report · notice · mapongoing
to 7:00 AMCITY OF FRANKENMUTH · Ardussi St manhole is designed to allow sanitary sewage to overflow into the stormwater piping during high flow events. · SSO (earlier version) · 88,322 gallons in all mapended
to 9:00 AMTuscola County Board of Public Works · The discharge location was through Chippewa Landing City Park · SSO · 5,000 gallons report · notice · mapended
to 8:00 PMCITY OF FRANKENMUTH · Air relief manhole in the W. Tuscola St force main system. · SSO · 400 gallons in all mapended
to 1:30 PMCITY OF FRANKENMUTH · City of Frankenmuth WRRF discharge line - 18" outfall line to the Cass river · SSO · 6,000 gallons report · notice · mapended
to 12:30 PMCITY OF FRANKENMUTH · 001 Outfall discharges into the Cass River via a 18" VCP effluent line. · CSO · 411 gallons report · notice · mapended
to Jun 10 ’21, 1:00 PMCITY OF FRANKENMUTH · Harlan Park Drain - Sanitary sewer manhole located in the Harlan park · SSO · 20,000 gallons report · notice · mapended
to 1:00 PMCITY OF FRANKENMUTH · City of Frankenmuth WRRF - [house number removed] Plant St. · Bypass · 42,000 gallons report · notice · mapended
to 10:00 AMCITY OF FRANKENMUTH · Frankenmuth Water Resource Facility - City wastewater plant, [house number removed] Plant st. see map · Bypass · 50,000 gallons report · notice · mapended
to 10:00 AMCITY OF FRANKENMUTH · W. Tuscola Lift Station - 900 block of W. Tuscola st See map · SSO · 50,000 gallons report · notice · mapended
to 9:25 AMCaro · WWTP - Outfall 001 · Bypass · 100 gallons report · notice · mapended
to 9:51 PMCaro · WWTP - Outfall 001 · SSO · 703,800 gallons report · notice · mapended
to 7:36 PMCaro · WWTP - Outfall 001 · SSO · 37,500 gallons report · notice · mapended
to 6:00 PMFrankenmuth · W. Tuscola Pump Station · SSO · 110,000 gallons report · notice · mapended
to 2:25 AMFrankenmuth · W. Tuscola Pump Station · SSO · 250 gallons report · notice · mapended
to Apr 29 ’09, 1:53 AMCaro · WWTP - Outfall 001 · SSO · 126,000 gallons report · notice · mapended
to 11:15 AMFrankenmuth · W. Tuscola Pump Station · SSO · 3,000 gallons report · notice · mapended

Sources: EGLE MiEnviro CSO/SSO List, retrieved 2026-11-05 01:07 UTC. A report's record id and times show when you hover or focus its "report" link.

Download these reports as CSV

Showing the latest 25 records of 39 records.See them all with filters.

All reports in Michigan by year: 2026 (9 here) · 2025 (3 here) · 2023 (2 here) · 2021 (1 here) · 2019 (3 here) · 2018 (1 here) · 2013 (2 here) · 2012 (2 here) · 2009 (3 here) · 2008 (1 here) · 2007 (2 here) · 2006 (2 here) · 2005 (2 here) · 2004 (2 here) · 2001 (4 here)

Wastewater outlets on this water

No wastewater outlet in our records is linked to this water.

Sewer operators listed for this water: Bridgeport Charter Township, CITY OF FRANKENMUTH, City of Vassar, Tuscola County Board of Public Works, Village of Cass City.

Boat launches

Source: OpenBoatLaunch launch records (public agency data and OpenStreetMap, Open Database License). · Cass River on OpenBoatLaunch

Nearby waters

Sources covering this water

35 records linked to this water, besides 4 earlier versions or duplicates. Updated .