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Maryland / Sewer operators /

Charles County Department of Public Works (Mattawoman WWTP)

Wastewater treatment plant · Maryland · Waldorf, La Plata, Indian Head

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)
MD0021865
Wastewater outlets
None with locations in our records
Waters listed as receiving wastewater
Mattawoman Creek; Potomac River
Tracked waters
Mattawoman Creek, MD, Potomac River, MD, Mattawoman Creek, MD, Zekiah Swamp Run, MD
Discharge records counted
23 records · latest
Total reported volume in these records
59,724,163 gallons across the 21 records that give a volume (2 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 Charles County Department of Public Works (Mattawoman WWTP) or the state publishes its notices (check them for an alert sign-up):

Source: Charles County Department of Public Works (Mattawoman WWTP)'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. Treatment bypass: wastewater skips one or more treatment steps.

Reports linked to Charles County Department of Public Works (Mattawoman WWTP), newest first
WhenReportStatus
to Sep 15, 6:30 PM“N/A” · 2300 Ironwood Drive · SSO · 3,500 gallons report · noticeended
to Aug 18, 5:40 AM“drainage ditch in the Pomonkey Creek” · 7062 Heather Drive · SSO · 58,022 gallons report · noticeended
Water not mapped · 9235 Mitchell Rd · Bypass · volume not reported report · noticereported
to 2:30 PM“Unnamed tributary of Mattawoman Creek” · 3945 Leonardtown rd · SSO · 1,200 gallons report · notice · mapended
to 12:42 PM“Groundwater.” · 13000 Pine Grove Rd · SSO · 10 gallons report · noticeended
to 2:45 PM“N/A - did not reach waters of the State” · 57296 Briarwood Drive · SSO · 255 gallons report · noticeended
to 1:00 PM“None.” · Bancroft Drive and Catskill St · SSO · 250 gallons report · notice · mapended
to 3:30 PM“A small unknown amount of the overflow went into the Festival @ Waldorf storm water management pond. Area was cleaned and limed as a precaution.” · 2971 Festival Way · SSO · 1,000 gallons report · noticeended
to 12:00 PM“N/A” · 5310 Hawthorne Road · SSO (earlier version) · 100 gallons in all ended
to 10:00 AM“NA - overflow was contained in stormwater retention pond” · 4225 Southwinds Place · SSO · 2,000 gallons report · noticeended
to May 19 ’24, 4:45 PMMattawoman Creek · Behind 10462 Cricket Court · SSO · 14,000 gallons report · notice · mapended
to May 16 ’24, 3:45 PMZekiah Swamp Run · Inter section of Saint Charles Parkway & Billingsley Road · SSO · 2.6 million gallons report · notice · mapended
to 12:30 PM“no impact to WUS” · 3040 Old Washington Rd. · SSO · 3,000 gallons report · noticeended
to Mar 13 ’24, 2:20 PM“Potomac River” · 5310 Hawthorne Rd · Bypass · 3.8 million gallons report · notice · mapended
to 2:30 PM“n/a” · 99 Smallwood Drive · SSO · 2,000 gallons report · noticeended
to 5:50 AM“No Discharge to State Waters” · 205 Jennifer Drive Indian Head · SSO · 30 gallons report · noticeended
to 8:15 PMMattawoman Creek · Prince Edward Drive & Kingsview Drive · SSO · 9,000 gallons report · notice · mapended
to 6:45 PM“None.” · St Charles Parkway and Post Office Rd · SSO (earlier version) · 16,000 gallons in all mapended
to 3:40 AM“n/a” · 5080 General Smallwood Drive · SSO · 12,000 gallons report · noticeended
to Jan 14 ’24, 10:15 AM“Potomac River” · 5310 Hawthorne Rd · Bypass · volume not reported report · notice · mapended
to Jan 16 ’24, 11:30 AM“Potomac River” · 5310 Hawthorne Rd · Bypass · 51.64 million gallons report · notice · mapended
to 1:30 AMMattawoman Creek · 6201 Livingston Rd. · Bypass · 60,000 gallons report · notice · mapended
to 3:00 AMMattawoman Creek · 6201 Livingston Road · SSO · 1.51 million 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

All reports in Maryland by year: 2026 (4 from Charles County Department of Public Works (Mattawoman WWTP)) · 2025 (3 from Charles County Department of Public Works (Mattawoman WWTP)) · 2024 (11 from Charles County Department of Public Works (Mattawoman WWTP)) · 2023 (7 from Charles County Department of Public Works (Mattawoman WWTP))

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.

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 2026-11-03 08:50 UTC.

Reported discharges over time

  • Discharges reported by Charles County Department of Public Works (Mattawoman WWTP), last 12 months5December 2025 to November 2026Verified reports where available, else notices; revisions and duplicates counted once.
  • Days with a discharge reported by Charles County Department of Public Works (Mattawoman WWTP), last 12 months7December 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 Charles County Department of Public Works (Mattawoman WWTP)'s reports, last 12 months43December 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 (Charles County Department of Public Works (Mattawoman WWTP))0.9%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

23 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.

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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. 1 discharge report has no end time and is not marked ongoing; under DirtyWaterWatch rules it shows caution, not a discharge or advisory status, and adds no hours here. 2 discharges reported to last more than 31 days are 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.

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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.

  • 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.

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Reported volume per year

Gallons (axis: K thousand, M million), summed from the 21 reports that gave a volume as a number (2 did not).

  • Incomplete source coverage
Limited records

2 of 23 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.

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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
  • Incomplete source coverage
Limited records

1 discharge report has no end time and is not marked ongoing; under DirtyWaterWatch rules it shows caution, not a discharge or advisory status, and adds no hours here. 2 discharges reported to last more than 31 days are 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.

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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

1 discharge report has no end time and is not marked ongoing; under DirtyWaterWatch rules it shows caution, not a discharge or advisory status, and adds no hours here. 2 discharges reported to last more than 31 days are 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.

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

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Reported discharges by wastewater outlet

Wastewater outlets with the most tracked discharge records: 10 of 21, 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