Water Quality
Water Quality > Hudson River Estuary Data > Rockland County & Westchester County Sites > Ossining Beach

Ossining Beach

Ossining Beach
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Physical/Chemical Data

Physical, chemical and biological properties of the surface water that are measured continuously while the patrol boat is underway.

Entero Count (fecal indicator) and Rainfall

108 Samples taken

Sample Date [i] Enterococcus Count
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Entero Count

Enterococcus (“Entero”) is a fecal indicating bacterium that lives in the intestines of humans and other warm-blooded animals. It is the EPA preferred indicator for sewage contamination.

Quality Rain, day of (in) Prior Day 2 Days Prior 3 Days Prior Rain 4 Days Total Rain
Sort Sort Sort Sort Sort Sort Sort Sort
10/17/2023 20 Acceptable 0.0 0.0 0.0 0.6 0.6
09/19/2023 249 Beach Advisory 0.0 1.0 0.2 0.1 1.3
08/22/2023 10 Acceptable 0.0 0.0 0.0 0.0 0.0
07/18/2023 41 Acceptable 0.0 0.0 1.4 0.2 1.6
06/27/2023 645 Beach Advisory 1.3 1.6 0.0 0.3 3.1
05/02/2023 10 Acceptable 0.0 0.2 2.2 1.6 4.0
10/10/2022 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
09/10/2022 52 Acceptable 0.0 0.0 0.0 2.1 2.1
08/12/2022 10 Acceptable 0.0 0.0 0.1 0.0 0.1
07/15/2022 10 Acceptable 0.0 0.0 0.0 0.0 0.0
06/14/2022 <10 Acceptable 0.1 0.0 0.0 0.0 0.1
05/24/2022 10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/29/2021 259 Beach Advisory 0.0 0.0 0.0 3.4 3.4
09/14/2021 107 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/17/2021 10 Acceptable 0.0 0.0 0.0 0.1 0.1
07/20/2021 <10 Acceptable 0.0 0.1 0.3 0.9 1.3
06/08/2021 10 Acceptable 0.0 0.0 0.0 0.0 0.0
05/17/2021 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/14/2020 10 Acceptable 0.0 0.3 0.3 0.0 0.6
09/18/2020 10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/14/2020 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
07/14/2020 <10 Acceptable 0.0 0.0 0.0 2.2 2.2
06/16/2020 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
05/26/2020 <10 Acceptable 0.0 0.0 0.0 0.2 0.2
10/08/2019 63 Beach Advisory 0.1 0.2 0.0 0.0 0.3
09/10/2019 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/06/2019 <10 Acceptable 0.0 0.0 0.2 0.9 1.1
07/09/2019 10 Acceptable 0.0 0.0 0.0 0.6 0.6
06/04/2019 52 Acceptable 0.0 0.0 0.0 0.0 0.0
05/07/2019 <10 Acceptable 0.0 0.1 1.1 0.1 1.3
10/10/2018 <10 Acceptable 0.0 0.0 0.1 0.0 0.1
09/10/2018 1130 Beach Advisory 1.7 0.1 0.1 0.0 1.9
08/14/2018 <10 Acceptable 0.0 0.8 0.2 1.9 2.9
07/17/2018 1470 Beach Advisory 1.6 0.1 0.3 0.5 2.5
06/13/2018 31 Acceptable 0.0 0.0 0.0 0.0 0.0
05/06/2018 85 Beach Advisory 0.2 0.0 0.0 0.3 0.5
10/16/2017 279 Beach Advisory 0.1 0.0 0.0 0.0 0.1
09/11/2017 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/14/2017 <10 Acceptable 0.0 0.0 0.4 0.3 0.7
07/10/2017 10 Acceptable 0.0 0.0 0.0 2.2 2.2
06/12/2017 31 Acceptable 0.0 0.0 0.0 0.0 0.0
05/16/2017 10 Acceptable 0.0 0.0 0.1 1.7 1.8
10/13/2016 <10 Acceptable 0.1 0.0 0.0 0.0 0.1
09/14/2016 20 Acceptable 0.0 0.0 0.0 0.0 0.0
08/15/2016 <10 Acceptable 0.0 0.1 0.1 0.2 0.4
07/13/2016 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
06/15/2016 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
05/21/2016 10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/12/2015 <10 Acceptable 0.0 0.0 0.0 0.1 0.1
09/11/2015 63 Beach Advisory 0.3 1.3 0.1 0.0 1.7
08/12/2015 <10 Acceptable 0.0 1.0 0.0 0.0 1.0
07/08/2015 31 Acceptable 0.0 0.1 0.0 0.0 0.1
06/11/2015 <10 Acceptable 0.0 0.0 0.2 0.2 0.4
05/12/2015 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/13/2014 <10 Acceptable 0.0 0.0 0.4 0.0 0.4
09/08/2014 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/12/2014 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
07/08/2014 10 Acceptable 0.2 0.0 0.0 0.0 0.2
06/13/2014 309 Beach Advisory 1.4 0.0 0.1 0.0 1.5
05/13/2014 20 Acceptable 0.0 0.0 0.1 0.3 0.4
10/17/2013 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
09/19/2013 10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/15/2013 41 Acceptable 0.0 0.0 0.7 0.4 1.1
07/18/2013 10 Acceptable 0.0 0.0 0.0 0.0 0.0
06/20/2013 10 Acceptable 0.0 0.0 0.3 0.2 0.5
05/30/2013 <10 Acceptable 0.0 0.0 0.4 0.0 0.4
10/11/2012 20 Acceptable 0.0 0.1 0.0 0.0 0.1
09/11/2012 10 Acceptable 0.0 0.0 0.0 1.4 1.4
08/14/2012 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
07/17/2012 <10 Acceptable 0.0 0.0 0.2 0.0 0.2
06/12/2012 20 Acceptable 0.5 0.0 0.0 0.0 0.5
05/16/2012 <10 Acceptable 0.1 0.4 0.1 0.0 0.6
10/20/2011 63 Beach Advisory 0.0 0.1 0.0 0.0 0.1
09/15/2011 31 Acceptable 0.0 0.0 0.0 0.0 0.0
08/17/2011 <10 Acceptable 0.0 0.0 0.0 3.4 3.4
08/15/2011 97 Beach Advisory 0.0 3.4 0.0 0.0 3.4
07/18/2011 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
06/28/2011 63 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/17/2011 4611 Beach Advisory 1.2 0.0 0.8 0.0 2.0
10/13/2010 <10 Acceptable 0.0 0.1 0.3 0.0 0.4
09/12/2010 10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/18/2010 <10 Acceptable 0.0 0.0 0.2 0.3 0.5
07/22/2010 441 Beach Advisory 0.0 0.1 0.0 1.4 1.5
06/16/2010 10 Acceptable 0.0 0.0 0.0 0.0 0.0
05/22/2010 10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/20/2009 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
09/15/2009 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/21/2009 10 Acceptable 0.0 0.0 0.0 0.0 0.0
07/29/2009 <10 Acceptable 0.0 0.0 0.0 0.2 0.2
06/23/2009 20 Acceptable 0.0 0.0 0.6 0.5 1.1
06/08/2009 <10 Acceptable 0.0 0.0 0.0 0.8 0.8
05/13/2009 10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/21/2008 41 Acceptable 0.0 0.0 0.0 0.0 0.0
09/23/2008 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/21/2008 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
07/15/2008 10 Acceptable 0.0 1.1 0.0 0.0 1.1
06/25/2008 1483 Beach Advisory 0.0 0.0 0.0 0.1 0.1
06/16/2008 6 Acceptable 0.0 0.0 1.7 0.0 1.7
05/20/2008 2420 Beach Advisory 0.0 0.0 0.2 0.1 0.3
09/09/2007 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/23/2007 48 Acceptable 0.0 0.0 1.3 0.1 1.4
07/16/2007 6 Acceptable 0.0 0.0 0.0 0.0 0.0
06/20/2007 11 Acceptable 0.1 0.3 0.0 0.0 0.4
05/21/2007 13 Acceptable 0.0 0.0 0.2 0.0 0.2
04/25/2007 43 Acceptable 0.0 0.0 0.0 0.0 0.0
12/06/2006 69 Beach Advisory 0.0 0.0 0.0 0.0 0.0
10/20/2006 15 Acceptable 0.4 0.1 0.0 1.1 1.6
09/19/2006 2 Acceptable 0.0 0.0 0.0 0.0 0.0

Entero Count (fecal indicator) and Rainfall Correlation

108 Samples taken

All Water Quality Parameters

108 Samples taken

Sample Date [i] Entero Count
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Entero Count

Enterococcus (“Entero”) is a fecal indicating bacterium that lives in the intestines of humans and other warm-blooded animals. It is the EPA preferred indicator for sewage contamination.

Quality [i] Temp (f)
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Temperature

Hudson River water temperature changes seasonally. Surface water temperature can change on small scales in the river reflecting natural and human influences.

[i] Salinity
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Salinity

Estuaries like the Hudson are where freshwaters in rivers meet the sea. Salinity tells us about the relative contribution of fresh and salt water within a particular region of the estuary. 

[i] Chlorophyll
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Chlorophyll

A measure of the amount of microscopic algae present in the water. High chlorophyll counts can mean high levels of the nutrients phosphorus and nitrogen, and the threat, or presence, of algae blooms.

[i] Turbidity
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Turbidity

Turbidity is a measure of the amount of fine particles suspended in the water. As turbidity rises, light penetration, a key factor for aquatic plants and algae, diminishes.

[i] Oxygen
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Oxygen

Oxygen concentrations in the water are closely connected to biological activities. Surface waters are typically in equilibrium with the atmosphere such that the oxygen concentration near the surface is close to fully saturated (100%).

Sort Sort Sort Sort Sort Sort Sort Sort
10/17/2023 20 Acceptable 16.19 3.37 1.06 4.1 103
09/19/2023 249 Beach Advisory 20.97 4.02 3.13 n/a n/a
08/22/2023 10 Acceptable 24.52 2.9 3.47 5.3 88.8
07/18/2023 41 Acceptable 26.91 0.38 2.46 14.3 83.5
06/27/2023 645 Beach Advisory 72.1 6.4 12.5 7.0 92.2
05/02/2023 10 Acceptable 54.7 1.8 2.2 13.7 92.9
10/10/2022 <10 Acceptable 62.7 9 5.5 3.6 96.7
09/10/2022 52 Acceptable 78.6 8.7 14.2 5 120
08/12/2022 10 Acceptable 82.6 9.3 8.5 5.1 122.1
07/15/2022 10 Acceptable 81.3 7.5 7.9 7.2 114.2
06/14/2022 <10 Acceptable 71.2 5.5 21.2 17.7 110.1
05/24/2022 10 Acceptable 64.4 4.6 3.1 11.7 99.9
10/29/2021 259 Beach Advisory 60.1 0.8 3.0 11 90
09/14/2021 107 Beach Advisory 74.5 1.0 5.8 20 93
08/17/2021 10 Acceptable 78.4 4.7 7.7 13 90
07/20/2021 <10 Acceptable 79.8 0.4 13.4 14 104
06/08/2021 10 Acceptable 70.5 4.1 13.9 9 104
05/17/2021 <10 Acceptable 69.9 1.0 6.0 19 117
10/14/2020 10 Acceptable 65.9 8.7 3.6 5 95
09/18/2020 10 Acceptable 71.9 9.6 14.1 10 108
08/14/2020 <10 Acceptable 84.2 5.4 17.4 10 106
07/14/2020 <10 Acceptable 83.6 6.8 20.1 7 136
06/16/2020 <10 Acceptable 73.5 4.8 12.4 10 125
05/26/2020 <10 Acceptable 68.5 3.9 9.0 8 127
10/08/2019 63 Beach Advisory 67.9 6.4 4.6 4 92
09/10/2019 <10 Acceptable 76.4 6.3 8.3 5 95
08/06/2019 <10 Acceptable 82.6 6.6 36.9 9 136
07/09/2019 10 Acceptable 82.3 4.3 29.0 10 145
06/04/2019 52 Acceptable 68.5 3.2 6.5 5 109
05/07/2019 <10 Acceptable 61.4 0.4 2.7 25 100
10/10/2018 <10 Acceptable 72.0 0.2 6.2 15 99
09/10/2018 1130 Beach Advisory 73.6 5.8 7.0 6 79
08/14/2018 <10 Acceptable 83.3 1.6 11.6 12 105
07/17/2018 1470 Beach Advisory 82.3 7.6 37.9 17 131
06/13/2018 31 Acceptable 70.5 6.1 114.4 18 159
05/06/2018 85 Beach Advisory 57.4 0.1 4.6 24 104
10/16/2017 279 Beach Advisory 67.5 7.8 5.0 18 92
09/11/2017 <10 Acceptable 71.9 7.1 8.0 8 104
08/14/2017 <10 Acceptable 81.0 4.6 13.2 9 108
07/10/2017 10 Acceptable 79.6 2.7 4.5 9 111
06/12/2017 31 Acceptable 77.7 0.8 9.6 11 132
05/16/2017 10 Acceptable 59.0 0.2 8.8 12 101
10/13/2016 <10 Acceptable 66.1 9.5 7.2 34 96
09/14/2016 20 Acceptable 81.8 8.0 5.7 n/a 119
08/15/2016 <10 Acceptable 87.0 5.2 20.3 31 136
07/13/2016 <10 Acceptable 81.0 5.9 13.3 10 112
06/15/2016 <10 Acceptable 71.8 3.5 7.4 21 109
05/21/2016 10 Acceptable 60.8 2.7 14.5 23 100
10/12/2015 <10 Acceptable 68.3 7.1 6.7 9 103
09/11/2015 63 Beach Advisory 79.1 8.2 9.3 18 90
08/12/2015 <10 Acceptable 82.7 6.8 19.1 11 147
07/08/2015 31 Acceptable 81.0 1.5 29.4 27 129
06/11/2015 <10 Acceptable 76.4 3.3 24.3 5 145
05/12/2015 <10 Acceptable 67.5 3.9 4.0 31 102
10/13/2014 <10 Acceptable 64.7 7.3 0.2 12 95
09/08/2014 <10 Acceptable 78.1 5.1 19.7 7 135
08/12/2014 <10 Acceptable 78.7 5.9 6.8 22 89
07/08/2014 10 Acceptable 79.4 1.3 6.0 25 97
06/13/2014 309 Beach Advisory 69.3 6.1 15.4 15 95
05/13/2014 20 Acceptable 60.2 3.0 2.1 18 99
10/17/2013 <10 Acceptable 67.4 7.4 3.0 6 88
09/19/2013 10 Acceptable 71.0 4.9 4.5 13 94
08/15/2013 41 Acceptable 75.8 3.4 13.6 17 119
07/18/2013 10 Acceptable 85.0 2.9 5.6 25 88
06/20/2013 10 Acceptable 71.1 0.3 3.7 16 96
05/30/2013 <10 Acceptable 68.8 0.8 1.2 28 95
10/11/2012 20 Acceptable 62.9 4.1 6.9 44 95
09/11/2012 10 Acceptable 76.0 6.5 6.4 18 93
08/14/2012 <10 Acceptable 82.1 7.4 4.4 12 96
07/17/2012 <10 Acceptable 83.1 8.3 23.4 8 133
06/12/2012 20 Acceptable 72.7 1.7 6.1 27 92
05/16/2012 <10 Acceptable 66.9 0.4 5.9 16 118
10/20/2011 63 Beach Advisory 63.4 0.3 0.7 118 92
09/15/2011 31 Acceptable 71.6 0.1 2.3 90 86
08/17/2011 <10 Acceptable 82.2 4.7 6.7 17 106
08/15/2011 97 Beach Advisory n/a n/a n/a n/a n/a
07/18/2011 <10 Acceptable 83.0 2.0 8.6 16 n/a
06/28/2011 63 Beach Advisory 80.5 1.5 12.5 15 115
05/17/2011 4611 Beach Advisory 61.0 1.7 n/a n/a 93
10/13/2010 <10 Acceptable 65.0 0.2 7.2 21 91
09/12/2010 10 Acceptable 71.3 6.3 19.6 20 91
08/18/2010 <10 Acceptable 80.8 7.1 9.2 159 100
07/22/2010 441 Beach Advisory 82.0 7.1 41.4 32 147
06/16/2010 10 Acceptable 73.3 6.2 12.2 16 91
05/22/2010 10 Acceptable 64.6 5.0 7.1 9 92
10/20/2009 <10 Acceptable 59.1 4.7 2.0 12 91
09/15/2009 <10 Acceptable 75.7 5.2 3.0 34 94
08/21/2009 10 Acceptable 83.3 3.6 20.6 15 124
07/29/2009 <10 Acceptable 79.6 2.0 5.7 23 96
06/23/2009 20 Acceptable 72.1 0.4 1.6 15 102
06/08/2009 <10 Acceptable n/a n/a n/a n/a n/a
05/13/2009 10 Acceptable 63.9 0.9 5.1 15 111
10/21/2008 41 Acceptable 60.9 7.7 3.7 6 93
09/23/2008 <10 Acceptable 72.4 5.4 2.4 6 94
08/21/2008 <10 Acceptable 77.5 4.8 12.9 15 113
07/15/2008 10 Acceptable 80.9 4.7 5.8 21 109
06/25/2008 1483 Beach Advisory 77.3 5.7 5.4 12 105
06/16/2008 6 Acceptable n/a n/a n/a n/a n/a
05/20/2008 2420 Beach Advisory 58.2 2.6 2.4 35 96
09/09/2007 <10 Acceptable 79.3 8.3 13.2 12 116
08/23/2007 48 Acceptable 75.0 6.6 3.4 6 82
07/16/2007 6 Acceptable 79.3 7.2 4.0 27 90
06/20/2007 11 Acceptable n/a n/a n/a n/a n/a
05/21/2007 13 Acceptable 62.6 0.7 2.7 55 97
04/25/2007 43 Acceptable 53.6 0.1 1.7 365 106
12/06/2006 69 Beach Advisory 44.5 0.2 1.4 9 96
10/20/2006 15 Acceptable n/a n/a n/a n/a n/a
09/19/2006 2 Acceptable n/a n/a n/a n/a n/a

Water Quality*

Acceptable (0–60) Beach Advisory (61+)

*Single sample thresholds;
Enterococcus count per 100mL

Prior Four Day Rainfall
(in inches)

Dry Weather (0–0.25) Wet Weather (0.25+)

Enterococcus is an EPA-approved fecal contamination indicator.

Samples taken by Riverkeeper, Lamont-Doherty Earth Observatory and CUNY Queens College staff, and processed on the Riverkeeper vessel, according to the 2014 Quality Assurance Project Plan.

Rainfall data comes from wunderground.com. Wet weather is a common trigger of fecal contamination.

What do the Numbers Mean?

Water Quality scoring is based on the 2012 Recreational Water Quality Criteria from the US Environmental Protection Agency (EPA) for safe swimming. Learn More

About this location:

Ossining, NY
Swimming at Ossining beach is prohibited, yet casual contact with the water has been observed. The beach is immediately north of a sewage treatment plant outfall. There is fishing, boating and kayaking at this site.

Agencies Responsible:

Westchester County Dept. of Health: 914-813-5000 and NYSDEC Region 3: 914-428-2505

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