DirtyWaterWatch Public waters. Public record.

Maryland / Sewer operators /

City of Rockville

Sewer utility · Maryland · Rockville

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)
not recorded
Wastewater outlets
None with locations in our records
Waters listed as receiving wastewater
Rock Creek; Watts Branch
Tracked waters
Rock Creek, MD, Watts Branch, MD, Cabin John Creek, MD, Seneca Creek, MD
Discharge records counted
14 records · latest
Total reported volume in these records
24,665 gallons across the 14 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 2026-11-03 08:50 UTC.

Public notices and alerts

Pages where City of Rockville or the state publishes its notices (check them for an alert sign-up):

Source: City of Rockville'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 City of Rockville, newest first
WhenReportStatus
to 11:00 AMRock Creek · 515 Dover Road · SSO · 100 gallons report · notice · mapended
to 12:00 PMRock Creek · 1680 East Gude Drive · SSO · 15 gallons report · notice · mapended
to 9:00 AMWatts Branch · 1510 West Montgomery Ave · SSO · 2,000 gallons report · notice · mapended
to 11:50 AM“Fallsgrove Stream” · SSO · 2,000 gallons report · noticeended
to 2:00 PMCabin John Creek · 600 Mount Vernon Place · SSO · 12,000 gallons report · notice · mapended
to 5:14 PM“stormwater management pond” · 1510 W. Montgomery Avenue · SSO · 400 gallons report · noticeended
to 1:30 PM“Part of overflow only reached street, part of overflow reached nearby storm drain” · 14 Beall Avenue · SSO (earlier version) · 200 gallons in all ended
to 5:00 PMWatts Branch · SSO · 150 gallons in all mapended
to 3:00 PMRock Creek · 1601 east gude drive · SSO · 1,000 gallons in all mapended
to 12:00 PM“Storm Drain to SWM Pond No Stream, river, etc. Private residence's sewer pit.” · 1601-1635 E. Gude Drive · SSO · 500 gallons report · noticeended
to Oct 11 ’23, 12:00 PMSeneca Creek · 15100 Frederick Rd · SSO · 400 gallons report · notice · mapended
to 12:00 PMWatts Branch · 1510 W. Montgomery Avenue · SSO · 6,000 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 (2 from City of Rockville) · 2025 (3 from City of Rockville) · 2024 (3 from City of Rockville) · 2023 (7 from City of Rockville)

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 City of Rockville, last 12 months4December 2025 to November 2026Verified reports where available, else notices; revisions and duplicates counted once.
  • Days with a discharge reported by City of Rockville, last 12 months4December 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 City of Rockville's reports, last 12 months6December 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 (City of Rockville)0.1%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

14 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. 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 14 reports that gave a volume as a number.

  • Incomplete source coverage
Limited records

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

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

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 11, 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