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Illinois / Sewer operators /

Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)

Sewer utility with combined sewers · Illinois · Chicago

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.

Solid dots mark combined sewer outfalls. Ringed dots mark treatment plant outfalls. Small hollow diamonds mark places named in its overflow reports (provisional). Grey dots are closed outfalls. A yellow ring with a dashed edge means discharge likely or possible: heavy rain, no report received. Dashed river stretches are estimates of where a discharge travels. Square boat markers mark boat launches listed by OpenBoatLaunch.

Federal wastewater discharge permit (NPDES)
IL0028061
Wastewater outlets
14 combined sewer outfalls and 3 treatment plant outfalls listed by EPA or state agencies; 2 places named in its own overflow reports (provisional locations) (the state's combined sewer records list 9) · List
Waters listed as receiving wastewater
LITTLE CALUMET RIVER; Midlothian Creek
Tracked waters
Calumet River, IL, Calumet Sag Channel, IL, Lake Michigan, IL, Little Calumet River, IL
Discharge records counted
9 records · latest
Total reported volume in these records
8,569,963,400 gallons across the 9 records that give a volume

These totals reflect the records we track. Missing volumes and gaps in reporting limit comparisons between operators.

Sources: EPA ECHO and the operator and state sources linked below. Counts use the discharge records on this page. Updated 2026-11-06 09:03 UTC.

Public notices and alerts

Get alerts from Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)

Pages where Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP) or the state publishes its notices:

Its public-notice channels

Source: Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)'s public notice and alert pages and the state's notification records; DirtyWaterWatch register of public-notice channels and its page monitor.

Report a missing notice or error

Rain and discharges

The NOAA MRMS radar-only rainfall estimate for the 24 hours to the latest hour, read every hour at each outfall from the radar grid. We show a caution when the rain reaches the amount below and no discharge report has arrived.

Threshold
0.1 in of rain in 24 hours (site default: This site's default: 0.1 inch of rain in 24 hours at a combined sewer outfall, applied where the state publishes no rain trigger of its own)
Radar now
2.7 in in the 24 hours to Nov 6, 2026, 2:00 AM CST
Forecast
0.01 in forecast in the next 24 hours (NWS forecast issued Nov 6, 2026, 12:21 AM CST)
Status
Discharge possible: heavy rain, no report received

Source: NOAA National Weather Service, MRMS radar-only rainfall estimate, valid Nov 6, 2026, 2:00 AM CST, retrieved 2026-11-06 08:57 UTC; threshold: site default; rule: How it works, discharge likely or possible.

Wastewater outlets

Outfall: a pipe or outlet where wastewater enters a water body.

14 combined sewer outfalls and 3 treatment plant outfalls listed by EPA or state agencies; 2 places named in its own overflow reports (provisional locations). Discharge likely or possible now at some of them: see Rain and discharges above.

Combined sewer outfalls

14 outfalls · 4 closed · discharge possible now at 9

Discharge possible: heavy rain, no report received at 9 outfalls now: radar rainfall has reached the operator's threshold and no discharge report has arrived (NOAA radar estimate).

  • Outfall 004 · receiving water in the permit: Little Calumet River · Little Calumet River, IL · open · discharge possible now: heavy rain, no report received
  • Outfall 151 · receiving water in the permit: Calumet River · Calumet River, IL · open · discharge possible now: heavy rain, no report received
  • Outfall 152 · receiving water in the permit: Calumet River · Calumet River, IL · open · discharge possible now: heavy rain, no report received
  • Outfall 153 · receiving water in the permit: LITTLE CALUMET RIVER · Little Calumet River, IL · open · discharge possible now: heavy rain, no report received
  • Outfall 154 · receiving water in the permit: Calumet Sag Channel · Calumet Sag Channel, IL · open · discharge possible now: heavy rain, no report received
  • Outfall 156 · receiving water in the permit: Calumet Sag Channel · Calumet Sag Channel, IL · open · discharge possible now: heavy rain, no report received
  • Outfall 157 · receiving water in the permit: Calumet Sag Channel · Calumet Sag Channel, IL · open · discharge possible now: heavy rain, no report received
  • Outfall 158 · receiving water in the permit: Calumet Sag Channel · Calumet Sag Channel, IL · open · discharge possible now: heavy rain, no report received
  • Outfall 163 · receiving water in the permit: Calumet Sag Channel · Calumet Sag Channel, IL · open · discharge possible now: heavy rain, no report received
  • Outfall 165 · receiving water in the permit: Midlothian Creek · no water record yet · closed
  • Outfall 166 · receiving water in the permit: Midlothian Creek · no water record yet · closed
  • Outfall 167 · receiving water in the permit: Midlothian Creek · no water record yet · closed

Showing 12 of 14.

Source: U.S. Environmental Protection Agency (EPA) national combined sewer outfall inventory (ECHO) and state outfall layers. Open or closed as EPA's inventory lists it. DirtyWaterWatch links outlets to waters using permit numbers, locations and names.

Treatment plant outfalls

3 outfalls

Source: U.S. Environmental Protection Agency (EPA) permit records (ICIS-NPDES permitted features): where a treatment plant’s permitted discharge leaves. No national source says whether a plant outfall is open or closed.

Places named in overflow reports (provisional)

2 places

Provisional location from overflow reports. Where the operator's own reports put an overflow: a manhole, pump station or plant. Not an outfall listed in a permit.

  • Reported place · 2 overflow reports, latest Jul 27, 2026 · confidence high · no water record yet
  • Reported place · 1 overflow report, latest Apr 2, 2025 · confidence medium · no water record yet

Source: the operator's own overflow reports to the state. DirtyWaterWatch groups reports within 50 metres into one place and finds the water below it with U.S. Geological Survey river maps (NLDI, NHDPlus). Not a permitted outfall; provisional until an official outfall record exists.

Reports and advisories

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. Combined sewer overflow (CSO): sewage mixed with rainwater spills from a shared sewer system.

Reports linked to Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP), newest first
WhenReportStatus
to 11:36 PM CDT“Mill Creek” · SSO · 1,200 gallons report · notice · mapended
to 6:30 AM CDT“Mill Creek” · SSO · 57,000 gallons report · notice · mapended
to 7:30 AM CST“Sony Creek” · Bypass · 20,700 gallons report · notice · mapended
to Apr 3 ’25, 4:30 AM CDT“Stony Creek” · SSO · 1.08 million gallons report · notice · mapended
to Apr 19 ’13Lake Michigan · OBrien Lock and Dam O'Brien Lock and Dam (Calumet River) · CSO · 3,185.6 million gallons report · notice · mapended
to Sep 16 ’08Lake Michigan · OBrien Lock and Dam O'Brien Lock and Dam (Calumet River) · CSO · 2,669.2 million gallons report · notice · mapended
to Feb 22, 1997Lake Michigan · OBrien Lock and Dam O'Brien Lock and Dam (Calumet River) · CSO · 1,458 million gallons report · notice · mapended
to Jul 18, 1996Lake Michigan · OBrien Lock and Dam O'Brien Lock and Dam (Calumet River) · CSO · 1,032 million gallons report · notice · mapended
to Nov 28, 1990Lake Michigan · OBrien Lock and Dam O'Brien Lock and Dam (Calumet River) · CSO · 224 million gallons report · notice · mapended

Sources: EPA ECHO Sewer Overflow and Bypass Event report (reported to regulators), retrieved 2026-11-06 08:38 UTC; MWRD Lake Michigan reversals table (1985 to present), retrieved 2026-11-06 08:41 UTC. A report's record id and times show when you hover or focus its "report" link.

Download these reports as CSV

All reports in Illinois by year: 2026 (3 from Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)) · 2025 (1 from Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)) · 2013 (1 from Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)) · 2008 (1 from Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)) · 1997 (1 from Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)) · 1996 (1 from Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)) · 1990 (1 from Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP))

Other sewer operators on these waters

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: a status resting on a source that could not be checked on schedule.

No discharge, advisory or caution periods are shown for the waters this sewer operator's reports were placed on in this time span. Check downstream stretches and source coverage.

Source: DirtyWaterWatch calculations using the reports named above and the published status rules. Updated 2026-11-06 09:03 UTC.

Reported discharges over time

  • Discharges reported by Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP), last 12 months3December 2025 to November 2026Verified reports where available, else notices; revisions and duplicates counted once.
  • Days with a discharge reported by Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP), last 12 months4December 2025 to November 2026A day counts once however many discharges were under way on it.
  • Hours with a discharge or advisory status from Metro Water Reclamation District Of Greater Chicago (MWRDGC Calumet WRP)'s reports, last 12 months10December 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.

Blended discharge: wastewater that skipped some treatment is mixed with treated wastewater.

Reported discharges per month

4 reported discharges, January 2022 to November 2026.

  • Combined sewer overflow
  • Sanitary sewer overflow
  • Treatment bypass, blended or other
  • No tracked source for this period
  • Incomplete source coverage
Limited records

No tracked source covers January 2022 to April 2022. The U.S. Environmental Protection Agency's sewer overflow records are limited: they hold only what operators file with the agency.

Source: U.S. Environmental Protection Agency sewer overflow records. Records cover May 3, 2022 to November 6, 2026.

Show table

Hours with a discharge or advisory status per month

Hours when a water had a discharge or advisory status from this sewer operator's reports, under DirtyWaterWatch rules.

  • Discharge or advisory reported
  • No tracked source for this period
  • Incomplete source coverage
Limited records

No tracked source covers January 2022 to April 2022. Official beach and cyanobacteria (harmful blue-green algae) advisories are counted on water pages only. The U.S. Environmental Protection Agency's sewer overflow records are limited: they hold only what operators file with the agency.

Source: U.S. Environmental Protection Agency sewer overflow records. Records cover May 3, 2022 to November 6, 2026.

Show table

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.

  • No tracked source for this period
  • Incomplete source coverage
Limited records

No tracked source covers January 2022 to April 2022.

Source: U.S. Environmental Protection Agency sewer overflow records. Records cover May 3, 2022 to November 6, 2026.

Show table

Reported volume per year

Gallons (axis: K thousand, M million), summed from the 4 reports that gave a volume as a number.

  • Incomplete source coverage
Limited records

Source: U.S. Environmental Protection Agency sewer overflow records. Records cover May 3, 2022 to November 6, 2026.

Show table

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
  • Incomplete source coverage
Limited records

Official beach and cyanobacteria (harmful blue-green algae) advisories are counted on water pages only.

Source: U.S. Environmental Protection Agency sewer overflow records. Records cover May 3, 2022 to November 6, 2026.

Show table

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: U.S. Environmental Protection Agency sewer overflow records. Records cover May 3, 2022 to November 6, 2026.

Show table
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)