Water Quality
Water Quality > Hudson River Estuary Data > Rockland County & Westchester County Sites > Saw Mill River

Saw Mill River

Saw Mill River
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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

117 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
06/10/2024 10 Acceptable 0.0 0.0 0.0 0.0 0.0
05/20/2024 10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/16/2023 20 Acceptable 0.0 0.0 0.6 0.0 0.6
09/18/2023 >24196 Beach Advisory 0.8 0.2 0.1 0.0 1.1
08/21/2023 108 Beach Advisory 0.0 0.0 0.0 1.3 1.3
07/17/2023 4352 Beach Advisory 0.0 1.4 0.2 1.0 2.6
06/26/2023 <10 Acceptable 0.0 0.0 0.3 0.2 0.5
05/01/2023 4106 Beach Advisory 0.2 2.2 1.6 0.1 4.1
10/09/2022 285 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/09/2022 <10 Acceptable 0.0 0.0 0.0 2.1 2.1
08/11/2022 20 Acceptable 0.0 0.0 0.1 0.0 0.1
07/14/2022 20 Acceptable 0.0 0.0 0.0 0.0 0.0
06/13/2022 24196 Beach Advisory 0.1 0.0 0.0 0.0 0.1
05/23/2022 175 Beach Advisory 0.0 0.0 0.0 0.0 0.0
10/25/2021 886 Beach Advisory 0.0 0.1 0.0 0.0 0.1
09/13/2021 20 Acceptable 0.0 0.0 0.0 0.0 0.0
08/16/2021 <10 Acceptable 0.0 0.0 0.1 0.0 0.1
07/19/2021 10 Acceptable 0.0 0.3 0.9 0.0 1.1
06/07/2021 275 Beach Advisory 0.0 0.0 0.0 0.1 0.1
05/17/2021 122 Beach Advisory 0.0 0.0 0.0 0.0 0.0
10/13/2020 2098 Beach Advisory 0.3 0.3 0.0 0.0 0.6
09/17/2020 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/13/2020 >24196 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/13/2020 259 Beach Advisory 0.0 0.0 2.2 0.9 3.1
06/15/2020 109 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/25/2020 74 Beach Advisory 0.0 0.0 0.2 0.0 0.2
10/07/2019 20 Acceptable 0.0 0.0 0.0 0.0 0.0
09/09/2019 41 Acceptable 0.0 0.0 0.0 0.0 0.0
08/05/2019 327 Beach Advisory 0.0 0.2 0.9 0.0 1.1
07/08/2019 51 Acceptable 0.0 0.0 0.6 0.0 0.6
06/03/2019 355 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/06/2019 959 Beach Advisory 0.1 1.1 0.1 0.0 1.4
10/09/2018 185 Beach Advisory 0.0 0.1 0.0 0.0 0.1
09/09/2018 241 Beach Advisory 0.0 0.1 0.0 0.0 0.1
08/13/2018 10462 Beach Advisory 0.8 0.2 1.9 0.0 2.8
07/17/2018 >24196 Beach Advisory 1.6 0.1 0.3 0.5 2.5
06/12/2018 121 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/06/2018 <10 Acceptable 0.2 0.0 0.0 0.3 0.5
10/15/2017 10 Acceptable 0.0 0.0 0.0 0.1 0.2
09/10/2017 20 Acceptable 0.0 0.0 0.0 0.1 0.1
08/13/2017 52 Acceptable 0.0 0.4 0.3 0.0 0.8
07/09/2017 134 Beach Advisory 0.0 0.0 2.2 0.0 2.2
06/11/2017 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
05/14/2017 1067 Beach Advisory 0.1 1.7 0.0 0.0 1.8
04/04/2017 20 Acceptable 1.1 0.0 0.0 0.1 1.2
10/12/2016 51 Acceptable 0.0 0.0 0.0 0.1 0.1
09/13/2016 20 Acceptable 0.0 0.0 0.0 0.2 0.2
08/14/2016 <10 Acceptable 0.0 0.1 0.2 0.3 0.5
07/12/2016 10 Acceptable 0.0 0.0 0.0 0.8 0.8
06/14/2016 <10 Acceptable 0.0 0.0 0.0 0.1 0.1
05/19/2016 63 Beach Advisory 0.0 0.0 0.0 0.0 0.0
10/11/2015 688 Beach Advisory 0.0 0.0 0.1 0.0 0.1
09/10/2015 6488 Beach Advisory 1.3 0.0 0.0 0.0 1.3
08/11/2015 19863 Beach Advisory 1.0 0.0 0.0 0.0 1.0
07/07/2015 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
06/10/2015 52 Acceptable 0.0 0.2 0.2 0.0 0.3
05/11/2015 31 Acceptable 0.0 0.0 0.0 0.0 0.0
10/12/2014 226 Beach Advisory 0.0 0.3 0.0 0.0 0.3
09/07/2014 350 Beach Advisory 0.0 0.1 0.0 0.0 0.1
08/11/2014 63 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/07/2014 <10 Acceptable 0.0 0.0 0.0 0.1 0.1
06/12/2014 201 Beach Advisory 0.0 0.0 0.0 1.6 1.6
05/12/2014 75 Beach Advisory 0.0 0.0 0.4 0.0 0.4
10/16/2013 86 Beach Advisory 0.0 0.0 0.0 0.0 0.0
09/18/2013 41 Acceptable 0.0 0.0 0.0 0.0 0.0
08/14/2013 959 Beach Advisory 0.0 0.9 0.1 0.0 0.9
07/17/2013 41 Acceptable 0.0 0.0 0.0 0.0 0.0
06/19/2013 31 Acceptable 0.0 0.2 0.0 0.0 0.2
05/31/2013 121 Beach Advisory 0.0 0.0 0.0 0.5 0.5
11/08/2012 134 Beach Advisory 0.1 1.1 0.0 0.0 1.2
10/10/2012 <10 Acceptable 0.3 0.0 0.0 0.2 0.5
09/10/2012 404 Beach Advisory 0.0 0.0 0.4 0.0 0.4
08/13/2012 368 Beach Advisory 0.0 0.0 0.0 0.2 0.2
07/16/2012 958 Beach Advisory 0.0 0.3 0.0 0.0 0.3
06/12/2012 98 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/16/2012 10 Acceptable 0.1 0.5 0.0 0.0 0.6
10/21/2011 31 Acceptable 0.0 0.0 1.1 0.0 1.1
09/15/2011 75 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/17/2011 24196 Beach Advisory 0.0 0.0 0.6 5.8 6.4
07/25/2011 19863 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/22/2011 10 Acceptable 0.0 0.0 0.0 0.0 0.0
07/21/2011 <10 Acceptable 0.0 0.0 0.0 0.1 0.1
07/18/2011 10 Acceptable 0.0 0.0 0.0 0.0 0.0
06/28/2011 959 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/17/2011 >24196 Beach Advisory 0.7 0.2 0.9 0.0 1.8
10/13/2010 816 Beach Advisory 0.0 0.1 1.1 0.0 1.2
09/12/2010 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
08/18/2010 85 Beach Advisory 0.0 0.0 0.1 0.2 0.3
07/22/2010 1274 Beach Advisory 0.0 0.0 0.0 0.1 0.1
06/16/2010 51 Acceptable 0.0 0.0 0.0 0.3 0.3
05/22/2010 41 Acceptable 0.0 0.0 0.0 0.0 0.0
10/19/2009 148 Beach Advisory 0.0 0.3 0.0 0.1 0.4
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 0.6 0.6
07/29/2009 86 Beach Advisory 0.0 0.0 0.6 1.4 2.0
06/23/2009 20 Acceptable 0.0 0.0 0.5 0.3 0.8
06/06/2009 10 Acceptable 0.0 0.9 0.5 0.5 1.9
05/13/2009 246 Beach Advisory 0.0 0.0 0.0 0.0 0.0
10/21/2008 10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/20/2008 20 Acceptable 0.0 0.0 0.0 0.0 0.0
10/20/2008 50 Acceptable 0.0 0.0 0.0 0.0 0.0
10/19/2008 10 Acceptable 0.0 0.0 0.0 0.0 0.0
09/23/2008 31 Acceptable 0.0 0.0 0.0 0.0 0.0
08/19/2008 20 Acceptable 0.0 0.0 0.0 0.0 0.0
07/14/2008 4229 Beach Advisory 0.5 0.0 0.0 0.0 0.5
07/02/2008 6488 Beach Advisory 0.0 0.0 0.0 0.6 0.6
06/24/2008 1427 Beach Advisory 0.0 0.1 0.1 0.0 0.2
05/19/2008 109 Beach Advisory 0.0 0.1 0.0 0.9 1.0
09/06/2007 123 Beach Advisory 0.0 0.0 0.0 0.0 0.0
08/16/2007 134 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/11/2007 11 Acceptable 0.0 0.0 0.0 0.0 0.0
06/28/2007 11 Acceptable 0.0 0.7 0.0 0.0 0.7
06/18/2007 19 Acceptable 0.0 0.0 0.0 0.0 0.0
05/23/2007 115 Beach Advisory 0.0 0.0 0.0 0.0 0.0
04/18/2007 1496 Beach Advisory 0.0 0.0 0.9 7.6 8.5
12/13/2006 1500 Beach Advisory 0.2 0.0 0.0 0.0 0.2
11/10/2006 1500 Beach Advisory 0.0 0.0 3.6 0.0 3.6

Entero Count (fecal indicator) and Rainfall Correlation

117 Samples taken

All Water Quality Parameters

117 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
06/10/2024 10 Acceptable 72.86 NS NS NS 85.0
05/20/2024 10 Acceptable 65.41 4.81 1.96 5.4 113.9
10/16/2023 20 Acceptable 61.88 5.89 1.2 8 103.7
09/18/2023 >24196 Beach Advisory 72.9 9.4 2.5 2 81
08/21/2023 108 Beach Advisory 74 5.4 4.4 74 85
07/17/2023 4352 Beach Advisory 70.6 0.7 5.1 48 99
06/26/2023 <10 Acceptable 72 9.2 15.1 8 118
05/01/2023 4106 Beach Advisory 54.4 0.9 4.7 50 98
10/09/2022 285 Beach Advisory 62.7 14.5 1.9 10 83
09/09/2022 <10 Acceptable 76.6 15.5 2.1 7 69
08/11/2022 20 Acceptable 81 15.5 4.8 7 80
07/14/2022 20 Acceptable 76.5 14 4.4 13 89
06/13/2022 24196 Beach Advisory 68.1 5.6 6 54 n/a
05/23/2022 175 Beach Advisory 62.7 8.3 2.2 30 91
10/25/2021 886 Beach Advisory 62.7 2.4 3.6 8 89
09/13/2021 20 Acceptable 73.5 4.1 2.6 25 80
08/16/2021 <10 Acceptable 77.2 9.2 6 24 78
07/19/2021 10 Acceptable 78.5 2.6 4.7 19 82
06/07/2021 275 Beach Advisory 69.5 6.7 2.7 11 93
05/17/2021 122 Beach Advisory 59.9 4.2 2.4 15 94
10/13/2020 2098 Beach Advisory 63.2 14.8 3.2 12 85
09/17/2020 <10 Acceptable 73.5 15.9 3.4 8 75
08/13/2020 >24196 Beach Advisory 81.8 7.6 185 15 149
07/13/2020 259 Beach Advisory 81.5 10.3 11 11 120
06/15/2020 109 Beach Advisory 71.2 8 9.9 11 118
05/25/2020 74 Beach Advisory 63.1 7.2 3.4 12 104
10/07/2019 20 Acceptable 67.8 11.6 2.7 7 88
09/09/2019 41 Acceptable 74.6 9.5 4.8 6 90
08/05/2019 327 Beach Advisory 80 12.4 3.6 15 60
07/08/2019 51 Acceptable 76.9 8.6 4.9 14 77
06/03/2019 355 Beach Advisory 66.1 5.5 1.7 12 92
05/06/2019 959 Beach Advisory 57.4 3.8 1.8 18 92
10/09/2018 185 Beach Advisory 70.7 7.4 2.3 16 73
09/09/2018 241 Beach Advisory 75.7 14.5 2.4 10 69
08/13/2018 10462 Beach Advisory 80.1 9.5 3.7 14 63
07/17/2018 >24196 Beach Advisory 77.8 15.9 4.5 15 69
06/12/2018 121 Beach Advisory 69.2 10.7 20.9 10 135
05/06/2018 <10 Acceptable 55.9 1.5 2.8 23 101
10/15/2017 10 Acceptable 70.2 13.9 2.6 8 80
09/10/2017 20 Acceptable 71 11.2 2.5 15 79
08/13/2017 52 Acceptable 77.4 9.7 3.1 12 77
07/09/2017 134 Beach Advisory 75 5 2.9 14 95
06/11/2017 <10 Acceptable 68.1 2.9 2 18 92
05/14/2017 1067 Beach Advisory 54.4 0.4 5 23 100
04/04/2017 20 Acceptable 48 0.3 12.1 43 100
10/12/2016 51 Acceptable 64.8 13.9 6.6 31 91
09/13/2016 20 Acceptable 76.7 11.5 36.7 n/a 133
08/14/2016 <10 Acceptable 83.8 8.8 51.5 16 165
07/12/2016 10 Acceptable 77.2 9.6 8.2 9 99
06/14/2016 <10 Acceptable 68.7 7.5 4.9 22 99
05/19/2016 63 Beach Advisory 59.3 6.4 2.8 n/a 96
10/11/2015 688 Beach Advisory 65.9 13.3 3 36 87
09/10/2015 6488 Beach Advisory 78.3 13.4 10 12 78
08/11/2015 19863 Beach Advisory 75.3 12.9 11.2 21 85
07/07/2015 <10 Acceptable 77.2 4.6 19.3 20 100
06/10/2015 52 Acceptable n/a n/a n/a n/a n/a
05/11/2015 31 Acceptable 66.8 5.6 2.8 26 98
10/12/2014 226 Beach Advisory 63.4 10.8 2.5 35 84
09/07/2014 350 Beach Advisory 77 12.2 4.4 19 81
08/11/2014 63 Beach Advisory 77.1 10 3.8 29 76
07/07/2014 <10 Acceptable 76.3 3.3 8 13 100
06/12/2014 201 Beach Advisory 66.5 8.4 32.1 19 104
05/12/2014 75 Beach Advisory 59.1 4 2 18 98
10/16/2013 86 Beach Advisory 65.7 14.8 2.4 15 80
09/18/2013 41 Acceptable 69.2 10.7 3 18 80
08/14/2013 959 Beach Advisory 75 7.4 6 46 87
07/17/2013 41 Acceptable 79.9 5.7 4.5 20 86
06/19/2013 31 Acceptable 69.2 2.4 4.2 26 92
05/31/2013 121 Beach Advisory 64.7 3.6 2.8 68 89
11/08/2012 134 Beach Advisory 50.7 8.5 1.1 21 93
10/10/2012 <10 Acceptable 64.9 8.5 5.7 4 86
09/10/2012 404 Beach Advisory 76.2 10.8 6.6 13 84
08/13/2012 368 Beach Advisory 80.7 12.2 14.8 8 106
07/16/2012 958 Beach Advisory 78.8 10.7 11.8 15 100
06/12/2012 98 Beach Advisory 70.9 6.7 5.7 25 85
05/16/2012 10 Acceptable 62.4 2.9 6.1 19 100
10/21/2011 31 Acceptable 62 2 1.3 41 92
09/15/2011 75 Beach Advisory 71 0.2 1.8 151 80
08/17/2011 24196 Beach Advisory 74 5.4 2.1 27 87
07/25/2011 19863 Beach Advisory 81.8 5.6 23.3 9 n/a
07/22/2011 10 Acceptable 84.8 5.4 32.2 18 209
07/21/2011 <10 Acceptable n/a n/a n/a n/a n/a
07/18/2011 10 Acceptable 79.8 6.6 2.9 32 n/a
06/28/2011 959 Beach Advisory 76.8 3.7 15.3 5 96
05/17/2011 >24196 Beach Advisory 57.7 0.6 n/a n/a 99
10/13/2010 816 Beach Advisory 64.2 2.1 3.6 18 86
09/12/2010 <10 Acceptable 72.7 11.2 3.5 15 70
08/18/2010 85 Beach Advisory 77.5 11.5 12 9 87
07/22/2010 1274 Beach Advisory 79.3 9.4 24.1 27 105
06/16/2010 51 Acceptable 71 10.4 3.4 34 73
05/22/2010 41 Acceptable 61.7 9.3 2.7 24 87
10/19/2009 148 Beach Advisory 54.4 9 1.9 20 90
09/15/2009 <10 Acceptable 71.6 9.7 2.5 50 87
08/21/2009 10 Acceptable 80.1 8.3 6.7 36 82
07/29/2009 86 Beach Advisory 77.2 5.7 3.3 26 81
06/23/2009 20 Acceptable 70.4 1.3 0.8 37 88
06/06/2009 10 Acceptable n/a n/a n/a n/a n/a
05/13/2009 246 Beach Advisory 59.1 2.2 1.2 14 97
10/21/2008 10 Acceptable 59.7 12.1 2.3 16 88
10/20/2008 20 Acceptable 61.7 15.4 1.9 15 82
10/20/2008 50 Acceptable 60.1 12.9 1.8 21 86
10/19/2008 10 Acceptable 62.2 17.5 1.6 33 81
09/23/2008 31 Acceptable 69.9 10.6 2 19 81
08/19/2008 20 Acceptable 77.6 8.6 2.3 12 92
07/14/2008 4229 Beach Advisory 75 6.8 4.3 71 93
07/02/2008 6488 Beach Advisory 75 9.5 6.3 32 88
06/24/2008 1427 Beach Advisory 72.7 9.2 2.5 30 86
05/19/2008 109 Beach Advisory 59.1 5.9 1.5 58 95
09/06/2007 123 Beach Advisory 74.9 13.3 2.8 17 83
08/16/2007 134 Beach Advisory 78.9 11.7 3.3 41 80
07/11/2007 11 Acceptable 76.4 12.6 7.2 15 93
06/28/2007 11 Acceptable 74.8 n/a n/a n/a 96
06/18/2007 19 Acceptable n/a n/a n/a n/a n/a
05/23/2007 115 Beach Advisory 63 2.5 1.2 49 93
04/18/2007 1496 Beach Advisory 42.8 0.4 0.5 77 99
12/13/2006 1500 Beach Advisory 45.4 2 1.3 12 100
11/10/2006 1500 Beach Advisory 53.8 1.3 1.5 45 95

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:

Yonkers, NY
The Sawmill River enters the Hudson at Yonkers. There is boating, kayaking, recreational and subsistence fishing in this area.

Agencies Responsible:

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

Tell Gov. Hochul to block invasive species at the Erie and Champlain canals
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