We test water quality at 31 locations in Marin County. We start the first week of April and end in the last week of October.
Beach Water Quality Monitoring Update
Seasonal water quality monitoring has concluded for 2025. Routine sampling will resume in April 2026.
Thank you for your interest in our water quality program. Please check back in the spring for updated results.
| Location | Week of 9/7/26 |
Week of 9/14/26 |
Week of 9/21/26 |
Week of 9/28/26 |
|---|---|---|---|---|
| Chicken Ranch Ditch - Channel B | AVOID | AVOID | AVOID | - |
| Chicken Ranch Beach | OK | OK | OK | - |
| Dillon Beach | OK | OK | OK | - |
| Dillon Beach Ditch | AVOID | AVOID | AVOID | - |
| Green Bridge | AVOID | OK | OK | - |
| Heart's Desire | OK | OK | OK | - |
| Inkwells | AVOID | OK | OK | - |
| Lawson's Landing | OK | OK | OK | - |
| Miller Park | OK | OK | OK | - |
| Millerton Point | OK | OK | OK | - |
| Shell Beach | OK | OK | OK | - |
| Drakes Beach | OK | OK | OK | - |
| Drakes Estero | OK | OK | OK | - |
| Whitehouse Pool | AVOID | AVOID | OK | - |
| Location | Week of 9/7/26 |
Week of 9/14/26 |
Week of 9/21/26 |
Week of 9/28/26 |
|---|---|---|---|---|
| Bolinas Beach | OK | OK | OK | - |
| China Camp | OK | OK | OK | - |
| Fort Baker, Horseshoe Cove - Southwest | N/A | N/A | N/A | - |
| Fort Baker, Horseshoe Cove - Northwest | OK | OK | OK | - |
| Fort Baker, Horseshoe Cove - Northeast | N/A | N/A | N/A | - |
| McNear's Beach | OK | AVOID | OK | - |
| Muir Beach - North | N/A | N/A | N/A | - |
| Muir Beach - Central | OK | OK | OK | - |
| Muir Beach - South | N/A | N/A | N/A | - |
| Paradise Beach | OK | OK | OK | - |
| Rodeo Beach - North | OK | OK | OK | - |
| Rodeo Beach - Central | N/A | N/A | N/A | - |
| Rodeo Beach - South | N/A | N/A | N/A | - |
| Schoonmaker Beach | OK | OK | OK | - |
| Stinson Beach - North | OK | OK | OK | - |
| Stinson Beach - Central | OK | OK | OK | - |
| Stinson Beach - South | N/A | N/A | N/A | - |
Related
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Beach water monitoring
Beach water samples are taken weekly to make sure the water is not contaminated and meets California's safety standards for swimming, wading, and other recreational activities.
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Current beach water samples map
Results are current April thru October each year. Most recent result only.