San Marcos Creek

Stream in California, past Carlsbad, Escondido, Lake San Marcos and San Marcos

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.

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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: Surface Water - Freshwater Harmful Algal Blooms (last successful check 2026-11-06 08:37 UTC). Status by DirtyWaterWatch, updated 2026-11-06 09:03 UTC. · Updated Nov 6, 2026, 1:03 AM PST

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 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 2026-11-06 09:03 UTC.

Reported discharges over time

Historical charts are not available here. See the reports and sources on this page.

Reports linked to San Marcos Creek

Cyanobacteria (harmful blue-green algae) can make water unfit for contact; the issuing authority decides when its advisory ends.

Reports linked to San Marcos Creek, newest first
When	Report	Status
Jul 14 ’23to Dec 21 ’23	California State Water Resources Control Board (FHAB program) · Lake San Marcos · Algae advisory · volume not reported report · notice · map	lifted
May 13 ’21to Dec 31 ’21	California State Water Resources Control Board (FHAB program) · Algae advisory · volume not reported report · notice · map	lifted
May 24 ’19to Dec 31 ’19	California State Water Resources Control Board (FHAB program) · Lake San Marcos, near Lakehouse Hotel · Algae advisory · volume not reported report · notice · map	lifted
Jun 20 ’17to Dec 31 ’17	California State Water Resources Control Board (FHAB program) · Lake San Marcos · Algae advisory · volume not reported report · notice · map	lifted

Sources: Surface Water - Freshwater Harmful Algal Blooms, retrieved 2026-11-06 03:07 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 California by year: 2023 (1 here) · 2021 (1 here) · 2019 (1 here) · 2017 (1 here)

Wastewater outlets on this water

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

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

Boat launches

No public boat launch is listed in our records for this water.

Nearby waters

Agua Hedionda Creek, CA No current status shown about 6 km away
Lake Hodges, CA No current status shown about 12 km away
Oceanside Harbor, CA No current status shown about 20 km away
Pilgrim Creek, CA No current status shown about 21 km away
Lake Miramar, CA No current status shown about 25 km away

Sources covering this water

Surface Water - Freshwater Harmful Algal Blooms · Latest check succeeded · Last successful check: 2026-11-06 08:37 UTC

4 records linked to this water. Updated Nov 6, 2026, 1:03 AM PST.