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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
6/1/26		 Week of
6/8/26		 Week of
6/15/26		 Week of
6/22/26		 Week of
6/29/26
Chicken Ranch Ditch - Channel B AVOID AVOID AVOID AVOID AVOID
Chicken Ranch Beach OK OK OK OK OK
Dillon Beach OK OK OK OK OK
Dillon Beach Ditch AVOID AVOID AVOID AVOID AVOID
Green Bridge OK OK OK OK OK
Heart's Desire OK OK OK OK OK
Inkwells OK OK OK AVOID OK
Lawson's Landing OK OK AVOID OK N/A
Miller Park OK OK OK OK OK
Millerton Point OK OK OK OK OK
Shell Beach OK OK OK OK OK
Drakes Beach OK OK N/A OK OK
Drakes Estero AVOID OK N/A OK OK
Whitehouse Pool  OK OK AVOID AVOID OK
Tuesday sample locations
Location Week of
6/1/26		 Week of
6/8/26		 Week of
6/15/26		 Week of
6/22/26		 Week of
6/29/26
Bolinas Beach                                                                                         OK OK - OK OK
China Camp OK OK N/A OK OK
Fort Baker, Horseshoe Cove - Southwest OK N/A N/A N/A N/A
Fort Baker, Horseshoe Cove - Northwest N/A OK N/A OK OK
Fort Baker, Horseshoe Cove - Northeast N/A N/A N/A N/A N/A
McNear's Beach OK OK N/A OK OK
Muir Beach - North N/A N/A N/A N/A N/A
Muir Beach - Central OK OK N/A OK OK
Muir Beach - South N/A N/A N/A N/A N/A
Paradise Beach OK OK N/A OK OK
Rodeo Beach - North OK OK N/A OK OK
Rodeo Beach - Central N/A N/A N/A N/A N/A
Rodeo Beach - South N/A N/A N/A N/A N/A
Schoonmaker Beach OK OK N/A OK OK
Stinson Beach - North OK OK N/A OK OK
Stinson Beach - Central OK OK N/A OK OK
Stinson Beach - South N/A N/A N/A N/A N/A

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Page last updated on July 6, 2026.

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