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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

Weekly results will appear here.

Monday sampling locations
Location Week of
10/5/26		 Week of
10/12/26		 Week of
10/19/26		 Week of
10/26/26
Chicken Ranch Ditch - Channel B AVOID AVOID AVOID AVOID
Chicken Ranch Beach OK OK OK OK
Dillon Beach OK OK OK OK
Dillon Beach Ditch OK AVOID AVOID OK
Green Bridge AVOID OK AVOID AVOID
Heart's Desire OK OK OK AVOID
Inkwells AVOID OK AVOID AVOID
Lawson's Landing OK OK OK OK
Miller Park OK OK OK OK
Millerton Point OK OK OK OK
Shell Beach OK OK OK OK
Drakes Beach OK N/A OK OK
Drakes Estero OK N/A OK OK
Whitehouse Pool  AVOID AVOID AVOID OK
Tuesday sample locations
Location Week of
10/5/26		 Week of
10/12/26		 Week of
10/19/26		 Week of
10/26/26
Bolinas Beach                                                                                         OK OK OK OK
China Camp OK OK OK OK
Fort Baker, Horseshoe Cove - Southwest N/A N/A AVOID N/A
Fort Baker, Horseshoe Cove - Northwest OK OK N/A OK
Fort Baker, Horseshoe Cove - Northeast N/A N/A N/A N/A
McNear's Beach OK OK OK OK
Muir Beach - North N/A N/A N/A N/A
Muir Beach - Central OK OK OK OK
Muir Beach - South N/A N/A N/A N/A
Paradise Beach OK OK OK OK
Rodeo Beach - North OK OK OK OK
Rodeo Beach - Central N/A N/A N/A N/A
Rodeo Beach - South N/A N/A N/A N/A
Schoonmaker Beach AVOID OK OK OK
Stinson Beach - North OK OK OK OK
Stinson Beach - Central OK OK N/A OK
Stinson Beach - South N/A N/A OK N/A

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Page last updated on November 5, 2026.

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