DirtyWaterWatch Public waters. Public record.

Maryland / Sewer operators /

WSSC Water (Washington Suburban Sanitary Commission)

Sewer utility · Maryland · Montgomery County, Prince George's County, Gaithersburg, Bethesda, Fort Washington, Adelphi, Laurel, Capitol Heights

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.

No outlet locations are in our records for this operator. Square boat markers mark boat launches listed by OpenBoatLaunch.

Federal wastewater discharge permit (NPDES)
MD0021539, MD0021491, MD0021741, MD0021725, MD0020982
Wastewater outlets
None with locations in our records
Waters listed as receiving wastewater
Western Branch; Northwest Branch; Rock Creek; Broad Creek; Paint Branch; Piscataway Creek; Muddy Branch; Anacostia River; Beaverdam Creek
Tracked waters
Anacostia River, MD, Piscataway Creek, MD, Potomac River, MD, Western Branch Patuxent River, MD, Patuxent River, MD, Anacostia River, DC, Little Falls Branch, MD, Northwest Branch, MD, Paint Branch, MD, Seneca Creek, MD, Sligo Creek, MD, Oxon Run, MD, Rock Creek, MD, Coquelin Run, MD, Cabin John Creek, MD, Patuxent River, MD, Henson Creek, MD, Gunners Branch, MD, Mill Creek, MD, Tinkers Creek, MD, Northwest Harbor, MD, Rock Run, MD, Northwest Branch Anacostia River, MD, Collington Branch, MD, Little Paint Branch, MD, Watts Branch, MD, Cabin Branch, MD, Muddy Branch, MD, Buck Branch, MD, Great Seneca Creek, MD, James Creek, MD, North Branch Rock Creek, MD, Mattawoman Creek, MD, Forest Glen Creek, MD, Hunters Mill Branch, MD
Discharge records counted
356 records · latest
Total reported volume in these records
443,301 gallons across the 347 records that give a volume (9 without one)

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 2026-11-03 08:50 UTC.

Public notices and alerts

Pages where WSSC Water (Washington Suburban Sanitary Commission) or the state publishes its notices (check them for an alert sign-up):

Source: WSSC Water (Washington Suburban Sanitary Commission)'s public notice and alert pages and the state's notification records.

Report a missing notice or error

Wastewater outlets

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

Reports and advisories

Sanitary sewer overflow (SSO): sewage spills from a sewer meant to carry sewage separately from rainwater.

Reports linked to WSSC Water (Washington Suburban Sanitary Commission), newest first
WhenReportStatus
to 8:30 PM“reporter stated no waterways were affected. UT to Magruder Branch (I-P) runs directly behind the address of the overflow.” · 24413 Galeano Way · SSO · 242 gallons report · noticeended
to 12:01 PMLittle Falls Branch · 5401 West Bard Avenue - NOT an SSO · SSO · 0 gallons report · notice · mapended
to Oct 19, 7:00 PM“Muddy Creek” · 12517 Lloydminster Drive · SSO · 1,558 gallons report · noticeended
to 3:00 PMPotomac River · Not Sewage · SSO · 0 gallons report · notice · mapended
to 7:45 PM“Unamed tributary to Lottsford Branch, b/t headwaters and confluence w/ Folly Branch. Use I waterway. 10/14/26 - No waterway impacted” · 12219 James Madison Lane · SSO · 374 gallons report · noticeended
to 4:30 PMNorthwest Branch · 12601 Spring Loch Court · SSO · 272 gallons report · notice · mapended
to 11:45 PMPaint Branch · 14255 Ballinger Court · SSO · 233 gallons report · notice · mapended
to 5:00 PMSeneca Creek · 110 Odendhal Avenue · SSO · 372 gallons report · notice · mapended
to 1:20 PMSligo Creek · 6729 Eastern Avenue · SSO · 177 gallons report · notice · mapended
to 11:35 PMPaint Branch · 13 Ballinger Court · SSO · 135 gallons report · notice · mapended
to 10:30 PMNorthwest Branch · 13118 Layhill Road · SSO · 128 gallons report · notice · mapended
to 5:01 PMWestern Branch Patuxent River · 8900 Crandall Road · SSO · 58 gallons report · notice · mapended
to 11:46 AMNorthwest Branch · 2421 Westiminster Drive · SSO · 5 gallons report · notice · mapended
to 4:50 PM“Broad Creek” · 10939 Mariner Drive · SSO · 1,500 gallons report · noticeended
to 11:10 AMOxon Run · 2011 Chadwick Terrace · SSO · 35 gallons report · notice · mapended
to 12:51 PM“NA” · 10239 Cove Ledge Court · SSO · 0 gallons report · noticeended
to 5:35 PMSeneca Creek · 110 Odenhal Avenue · SSO · 468 gallons report · notice · mapended
to 9:23 AM“Along property line. N/A” · 25 Holt Place · SSO · 0 gallons report · noticeended
to 2:00 PM“none” · 1415 Pinelake Lane · SSO · 63 gallons report · noticeended
to 3:00 PMWestern Branch Patuxent River · 1415 Pinelake Lane · SSO · 63 gallons report · notice · mapended
to 4:00 PM“Northeast Branch” · 6407 Kenilworth Avenue · SSO · 10 gallons report · noticeended
to 8:15 PMPaint Branch · 11503-56 February Circle · SSO · 810 gallons report · notice · mapended
to 9:30 PM“Broad Creek” · 3004 Plaza Drive · SSO · 880 gallons report · notice · mapended
to 11:30 PM“entered stormdrain” · 2807 Nicholson st · SSO · 276 gallons report · noticeended
to 5:30 PMRock Creek · 12806 Turkey Branch Parkway · SSO · 200 gallons report · notice · mapended

Sources: MDE Reported Sewer Overflows (New for 2023), Maryland Open Data Portal (Socrata stgj-u72u), retrieved 2026-11-03 08:17 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 369 records.See them all with filters.

All reports in Maryland by year: 2026 (89 from WSSC Water (Washington Suburban Sanitary Commission)) · 2025 (103 from WSSC Water (Washington Suburban Sanitary Commission)) · 2024 (95 from WSSC Water (Washington Suburban Sanitary Commission)) · 2023 (82 from WSSC Water (Washington Suburban Sanitary Commission))

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. Grey: no current status on the water outline. Purple hatching: source update overdue.
  • Caution: to
    1 report: Little Falls Branch 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Little Falls Branch 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    1 report: Potomac River 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Potomac River 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    2 reports: Northwest Branch 1, Paint Branch 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Northwest Branch 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    2 reports: Paint Branch 1, Seneca Creek 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Paint Branch 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    2 reports: Paint Branch 1, Seneca Creek 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Seneca Creek 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    2 reports: Paint Branch 1, Sligo Creek 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    2 reports: Paint Branch 1, Sligo Creek 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    2 reports: Northwest Branch 1, Western Branch Patuxent River 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Northwest Branch 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    3 reports: Northwest Branch 1, Oxon Run 1, Western Branch Patuxent River 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Western Branch Patuxent River 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    3 reports: Northwest Branch 1, Oxon Run 1, Seneca Creek 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Northwest Branch 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    2 reports: Oxon Run 1, Seneca Creek 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Oxon Run 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    1 report: Seneca Creek 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Seneca Creek 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    1 report: Western Branch Patuxent River 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Western Branch Patuxent River 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    1 report: Paint Branch 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Paint Branch 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    2 reports: Coquelin Run 1, Rock Creek 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Rock Creek 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    2 reports: Coquelin Run 1, Western Branch Patuxent River 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Coquelin Run 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    1 report: Western Branch Patuxent River 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Western Branch Patuxent River 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    1 report: Potomac River 1
    Show records

    The records are also in the report table on this page.

  • Caution: to
    1 report: Potomac River 1
    Show records

    The records are also in the report table on this page.

  • Discharge or advisory reported: to
    1 report: Potomac River 1
    Show records

    The records are also in the report table on this page.

Source: DirtyWaterWatch calculations using the reports named above and the published status rules. Updated 2026-11-03 08:50 UTC.

Reported discharges over time

  • Discharges reported by WSSC Water (Washington Suburban Sanitary Commission), last 12 months102December 2025 to November 2026Verified reports where available, else notices; revisions and duplicates counted once.
  • Days with a discharge reported by WSSC Water (Washington Suburban Sanitary Commission), last 12 months97December 2025 to November 2026A day counts once however many discharges were under way on it. Verified reports where available, else notices; revisions and duplicates counted once.
  • Hours with a discharge or advisory status from WSSC Water (Washington Suburban Sanitary Commission)'s reports, last 12 months1,152December 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 (WSSC Water (Washington Suburban Sanitary Commission))4.2%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.

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

356 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
No tracked source

No tracked source covers January 2022 to December 2022.

Source: md-mde-overflows. Records cover January 4, 2023 to November 3, 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
No tracked source

No tracked source covers January 2022 to December 2022. 6 discharge reports have no end time and are not marked ongoing; under DirtyWaterWatch rules they show caution, not a discharge or advisory status, and add no hours here. 1 discharge reported to last more than 31 days is counted as 31 days. Official beach and cyanobacteria (harmful blue-green algae) advisories are counted on water pages only.

Source: md-mde-overflows. Records cover January 4, 2023 to November 3, 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
No tracked source

No tracked source covers January 2022 to December 2022.

Source: md-mde-overflows. Records cover January 4, 2023 to November 3, 2026.

Show table

Reported volume per year

Gallons (axis: K thousand, M million), summed from the 347 reports that gave a volume as a number (9 did not).

  • Incomplete source coverage
Limited records

9 of 356 discharge reports gave no volume as a number; only numbers are summed.

Source: md-mde-overflows. Records cover January 4, 2023 to November 3, 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

6 discharge reports have no end time and are not marked ongoing; under DirtyWaterWatch rules they show caution, not a discharge or advisory status, and add no hours here. 1 discharge reported to last more than 31 days is counted as 31 days. Official beach and cyanobacteria (harmful blue-green algae) advisories are counted on water pages only.

Source: md-mde-overflows. Records cover January 4, 2023 to November 3, 2026.

Show table

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

6 discharge reports have no end time and are not marked ongoing; under DirtyWaterWatch rules they show caution, not a discharge or advisory status, and add no hours here. 1 discharge reported to last more than 31 days is counted as 31 days. Official beach and cyanobacteria (harmful blue-green algae) advisories are counted on water pages only.

Source: md-mde-overflows. Records cover January 4, 2023 to November 3, 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: md-mde-overflows. Records cover January 4, 2023 to November 3, 2026.

Show table

Reported discharges by wastewater outlet

Wastewater outlets with the most tracked discharge records: 10 of 343, all years. Counts depend on reporting coverage and do not measure legal compliance or harm.

Source: md-mde-overflows. Records cover January 4, 2023 to November 3, 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.

  • md-mde-overflows: records from January 4, 2023 to the latest update