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Beach water quality information

List of weekly test results from April to October.

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.

Monday sampling locations
Location Week of
7/6/26		 Week of
7/13/26		 Week of
7/20/26		 Week of
7/27/26		 Week of
8/3/26
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 OK AVOID OK    
Heart's Desire OK OK OK    
Inkwells OK AVOID OK    
Lawson's Landing OK OK OK    
Miller Park OK N/A OK    
Millerton Point OK N/A OK    
Shell Beach OK OK OK    
Drakes Beach OK OK OK    
Drakes Estero OK OK OK    
Whitehouse Pool  OK AVOID OK    
Tuesday sample locations
Location Week of
7/6/26		 Week of
7/13/26		 Week of
7/20/26		 Week of
7/27/26		 Week of
8/3/26
Bolinas Beach                                                                                         OK AVOID 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 OK OK    
Muir Beach - North N/A N/A N/A    
Muir Beach - Central N/A OK N/A    
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 AVOID OK    
Stinson Beach - North OK OK OK    
Stinson Beach - Central OK OK OK    
Stinson Beach - South N/A N/A N/A    

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Page last updated on July 23, 2026.

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