Water Quality
Water Quality > Hudson River Estuary Data > Rockland County & Westchester County Sites > Yonkers Sewage Treatment Plant Outfall

Yonkers Sewage Treatment Plant Outfall

Yonkers WWTP Outfall
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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

116 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
10/16/2023 20 Acceptable 0.0 0.0 0.6 0.0 0.6
09/18/2023 63 Beach Advisory 0.8 0.1 0.0 0.0 0.9
08/21/2023 <10 Acceptable 0.0 0.0 0.0 1.3 1.3
07/17/2023 84 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 292 Beach Advisory 0.2 2.2 1.6 0.1 4.1
10/09/2022 <10 Acceptable 0.0 0.0 0.0 1.8 1.8
09/09/2022 10 Acceptable 0.0 0.0 2.1 0.7 2.8
08/11/2022 20 Acceptable 0.0 0.1 0.0 0.1 0.3
07/14/2022 20 Acceptable 0.0 0.0 0.0 0.0 0.0
06/13/2022 85 Beach Advisory 0.0 0.0 0.0 1.4 1.4
05/23/2022 218 Beach Advisory 0.0 0.0 0.0 0.2 0.2
10/25/2021 20 Acceptable 0.0 0.1 0.0 0.0 0.1
09/13/2021 <10 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 10 Acceptable 0.0 0.0 0.0 0.1 0.1
05/17/2021 41 Acceptable 0.0 0.0 0.0 0.0 0.0
10/13/2020 73 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 1782 Beach Advisory 0.0 0.0 0.0 0.0 0.0
07/13/2020 10 Acceptable 0.0 0.0 2.2 0.9 3.1
06/15/2020 20 Acceptable 0.0 0.0 0.0 0.0 0.0
05/25/2020 41 Acceptable 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 20 Acceptable 0.0 0.0 0.0 0.0 0.0
08/05/2019 63 Beach Advisory 0.0 0.2 0.9 0.0 1.1
07/08/2019 52 Acceptable 0.0 0.0 0.6 0.0 0.6
06/03/2019 52 Acceptable 0.0 0.0 0.0 0.0 0.1
05/06/2019 301 Beach Advisory 0.1 1.1 0.1 0.0 1.3
10/09/2018 62 Beach Advisory 0.0 0.1 0.0 0.0 0.1
09/09/2018 <10 Acceptable 0.0 0.1 0.0 0.0 0.1
08/13/2018 122 Beach Advisory 0.8 0.2 1.9 0.0 2.8
07/17/2018 2755 Beach Advisory 1.6 0.1 0.3 0.5 2.5
06/12/2018 148 Beach Advisory 0.0 0.0 0.0 0.0 0.0
05/06/2018 86 Beach Advisory 0.2 0.0 0.0 0.3 0.5
10/15/2017 20 Acceptable 0.0 0.0 0.0 0.1 0.2
09/10/2017 <10 Acceptable 0.0 0.0 0.0 0.1 0.1
08/13/2017 31 Acceptable 0.0 0.4 0.3 0.0 0.8
07/09/2017 41 Acceptable 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 189 Beach Advisory 0.1 1.7 0.0 0.0 1.8
04/04/2017 110 Beach Advisory 1.1 0.0 0.0 0.1 1.2
10/12/2016 20 Acceptable 0.0 0.0 0.0 0.1 0.1
09/13/2016 <10 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 31 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 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/11/2015 60 Acceptable 0.0 0.0 0.1 0.0 0.1
09/10/2015 10 Acceptable 1.3 0.0 0.0 0.0 1.3
08/11/2015 98 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 <10 Acceptable 0.0 0.2 0.2 0.0 0.3
05/11/2015 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
10/12/2014 <10 Acceptable 0.0 0.3 0.0 0.0 0.3
09/07/2014 <10 Acceptable 0.0 0.1 0.0 0.0 0.1
08/11/2014 <10 Acceptable 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 10 Acceptable 0.0 0.0 0.0 1.6 1.6
05/12/2014 20 Acceptable 0.0 0.0 0.4 0.0 0.4
10/16/2013 31 Acceptable 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 75 Beach Advisory 0.0 0.9 0.1 0.0 0.9
07/17/2013 20 Acceptable 0.0 0.0 0.0 0.0 0.0
06/19/2013 41 Acceptable 0.0 0.2 0.0 0.0 0.2
05/31/2013 20 Acceptable 0.0 0.0 0.0 0.5 0.5
11/08/2012 2400 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 30 Acceptable 0.0 0.0 0.4 0.0 0.4
08/13/2012 <10 Acceptable 0.0 0.0 0.0 0.2 0.2
07/16/2012 <10 Acceptable 0.0 0.3 0.0 0.0 0.3
06/12/2012 <10 Acceptable 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 85 Beach Advisory 0.0 0.0 1.1 0.0 1.1
09/15/2011 20 Acceptable 0.0 0.0 0.0 0.0 0.0
08/17/2011 <10 Acceptable 0.0 0.0 0.6 5.8 6.4
07/25/2011 86 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 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
05/17/2011 20 Acceptable 0.7 0.2 0.9 0.0 1.7
10/13/2010 31 Acceptable 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 <10 Acceptable 0.0 0.0 0.1 0.2 0.3
07/22/2010 <10 Acceptable 0.0 0.0 0.0 0.1 0.1
06/16/2010 <10 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 10 Acceptable 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 <10 Acceptable 0.0 0.0 0.6 1.4 2.0
06/23/2009 <10 Acceptable 0.0 0.0 0.5 0.3 0.7
06/06/2009 10 Acceptable 0.0 0.9 0.5 0.5 2.0
05/13/2009 10 Acceptable 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 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
10/19/2008 20 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
08/19/2008 10 Acceptable 0.0 0.0 0.0 0.0 0.0
07/14/2008 15 Acceptable 0.5 0.0 0.0 0.0 0.5
07/02/2008 15 Acceptable 0.0 0.0 0.0 0.6 0.6
06/24/2008 13 Acceptable 0.0 0.1 0.1 0.0 0.1
05/19/2008 20 Acceptable 0.0 0.1 0.0 0.9 1.1
09/06/2007 18 Acceptable 0.0 0.0 0.0 0.0 0.0
08/16/2007 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
07/11/2007 <10 Acceptable 0.0 0.0 0.0 0.0 0.0
06/18/2007 3 Acceptable 0.0 0.0 0.0 0.0 0.0
05/23/2007 6 Acceptable 0.0 0.0 0.0 0.0 0.0
04/18/2007 103 Beach Advisory 0.0 0.0 0.9 7.6 8.5
12/13/2006 40 Acceptable 0.2 0.0 0.0 0.0 0.2
11/10/2006 22 Acceptable 0.0 0.0 3.6 0.0 3.6
10/18/2006 12 Acceptable 0.0 1.1 0.0 0.0 1.1
09/26/2006 23 Acceptable 0.0 0.0 0.0 0.1 0.1

Entero Count (fecal indicator) and Rainfall Correlation

116 Samples taken

All Water Quality Parameters

116 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
10/16/2023 20 Acceptable 16.36 6.5 1.22 10.4 103.3
09/18/2023 63 Beach Advisory 22.67 9.59 2.44 2.1 71.4
08/21/2023 <10 Acceptable 24.23 6.58 3.23 93.2 70.7
07/17/2023 84 Beach Advisory 25.9 2.55 2.5 87 82.1
06/26/2023 <10 Acceptable 71.8 11.3 13.0 16.3 112.1
05/01/2023 292 Beach Advisory 54.1 2.0 2.2 16.9 96.3
10/09/2022 <10 Acceptable 62.8 14.9 1.9 11.3 78.8
09/09/2022 10 Acceptable 76.5 16.2 2.1 8.1 65
08/11/2022 20 Acceptable 79 17.8 2.6 9.4 65.6
07/14/2022 20 Acceptable 75 15.1 3.3 14.7 78.2
06/13/2022 85 Beach Advisory 69.1 10 3.1 29.7 n/a
05/23/2022 218 Beach Advisory 62.4 9.1 2.6 73.4 88.4
10/25/2021 20 Acceptable 62.996 2.5 3.49 8.2 87
09/13/2021 <10 Acceptable 73.85 3.68 3.07 23.6 81.8
08/16/2021 10 Acceptable 77.054 9.44 5.89 20.5 77.7
07/19/2021 <10 Acceptable 78.53 2.54 4.79 12.5 81.2
06/07/2021 10 Acceptable 69.836 7.47 2.5 9.5 82.3
05/17/2021 41 Acceptable 59.954 4.66 2.75 21.6 93.4
10/13/2020 73 Beach Advisory 63.554 15.4 3.26 19.4 85.8
09/17/2020 <10 Acceptable 73.238 15.97 2.33 12.3 67.9
08/13/2020 1782 Beach Advisory 81.122 9.6 139.82 12.6 132.1
07/13/2020 10 Acceptable 78.746 10.61 5.78 11.5 85.8
06/15/2020 20 Acceptable 70.556 9.84 8.38 10.2 114.1
05/25/2020 41 Acceptable 61.232 9.87 2.9 13 99.3
10/07/2019 20 Acceptable 69.098 12.18 2.8 7.6 76.9
09/09/2019 20 Acceptable 74.066 11.09 3.28 6 82.3
08/05/2019 63 Beach Advisory 79.088 13.4 2.78 26.7 55.1
07/08/2019 52 Acceptable 75.812 8.8 3.71 17.6 71.2
06/03/2019 52 Acceptable 64.148 8.57 1.74 14.5 76
05/06/2019 301 Beach Advisory 57.254 4.93 1.46 20.1 91.4
10/09/2018 62 Beach Advisory 70.826 7.65 2.55 20.5 72.5
09/09/2018 <10 Acceptable 76.208 15.64 2.32 11.5 65.5
08/13/2018 122 Beach Advisory 78.89 10.39 3.89 14.7 60.3
07/17/2018 2755 Beach Advisory 76.406 16.37 3.05 15 62.2
06/12/2018 148 Beach Advisory 68.108 11.94 14.94 12.3 116
05/06/2018 86 Beach Advisory 55.364 1.51 2.14 21.8 101.4
10/15/2017 20 Acceptable 70.322 13.45 2.36 9.6 77.8
09/10/2017 <10 Acceptable 70.862 13.06 2.6 27.1 72
08/13/2017 31 Acceptable 76.316 9.55 2.31 42.8 69.6
07/09/2017 41 Acceptable 75.254 7.05 2.95 9.9 98.4
06/11/2017 <10 Acceptable 67.226 4.38 2.29 22.9 85.1
05/14/2017 189 Beach Advisory 57.668 3.44 2.38 22.4 98.1
04/04/2017 110 Beach Advisory 41.756 0.93 1.93 32.3 99.2
10/12/2016 20 Acceptable 65.948 14 4.01 30.5 84.7
09/13/2016 <10 Acceptable 76.388 13.24 19.3 n/a 112
08/14/2016 10 Acceptable 82.382 10.91 44.54 18.5 148.9
07/12/2016 31 Acceptable 77.072 10.72 8.43 10.2 101.5
06/14/2016 <10 Acceptable 68.396 8.42 4.2 32.3 97
05/19/2016 <10 Acceptable 59.576 6.16 2.73 n/a 97.8
10/11/2015 60 Acceptable 66.38 14.42 2.53 32 79.3
09/10/2015 10 Acceptable 78.026 16.51 4.09 13.6 65.2
08/11/2015 98 Beach Advisory 75.902 14.48 6 21.2 80.4
07/07/2015 10 Acceptable 77.306 5.12 13.52 32.9 96.4
06/10/2015 <10 Acceptable n/a n/a n/a n/a n/a
05/11/2015 <10 Acceptable 61.52 9.97 2.78 45 91.2
10/12/2014 <10 Acceptable 65.03 12.27 2.17 48 74.7
09/07/2014 <10 Acceptable 76.478 13.64 3.16 22.3 72.9
08/11/2014 <10 Acceptable 76.388 12.62 2.87 85.5 67.1
07/07/2014 10 Acceptable 75.758 4.22 7.89 11.1 99.4
06/12/2014 10 Acceptable 66.308 12.08 27.33 24.3 103.7
05/12/2014 20 Acceptable 57.83 5.19 2.04 20.9 96.5
10/16/2013 31 Acceptable 65.804 15.66 2.36 16.7 77.6
09/18/2013 41 Acceptable 69.98 14.02 2.81 43.3 70.3
08/14/2013 75 Beach Advisory 75.812 8.34 5.25 25.4 82.3
07/17/2013 20 Acceptable 79.034 7.61 3.94 19.9 82.3
06/19/2013 41 Acceptable 69.008 2.79 3.6 19 91.8
05/31/2013 20 Acceptable 64.742 3.54 2.49 68.2 89.9
11/08/2012 2400 Beach Advisory 51.944 9.11 1.02 21.6 89.2
10/10/2012 <10 Acceptable 65.282 10.37 5.43 4.3 84.5
09/10/2012 30 Acceptable 76.064 11.38 5.43 15.1 82.1
08/13/2012 <10 Acceptable 80.51 12.73 13.43 8 99.6
07/16/2012 <10 Acceptable 76.622 17.7 4.33 15 72.4
06/12/2012 <10 Acceptable 70.916 7.45 5.36 23.9 80.2
05/16/2012 10 Acceptable 62.06 3.53 4.57 18.1 97.4
10/21/2011 85 Beach Advisory 62.726 2.57 1.39 70.5 90
09/15/2011 20 Acceptable 70.88 0.22 1.82 133.8 80.8
08/17/2011 <10 Acceptable 77.774 8.3 2.01 110 71.7
07/25/2011 86 Beach Advisory 80.7 8.27 19.7 13.4 n/a
07/22/2011 <10 Acceptable 84 6.36 27.97 15.4 155.6
07/21/2011 <10 Acceptable n/a n/a n/a n/a n/a
07/18/2011 <10 Acceptable 77.468 6.3 2.39 54 n/a
06/28/2011 <10 Acceptable 75.038 5.09 8.15 1.6 96.6
05/17/2011 20 Acceptable 59.18 5.29 n/a n/a 68.2
10/13/2010 31 Acceptable 64.472 2.4 3.51 15.8 85
09/12/2010 10 Acceptable 73.04 12.4 3.71 60 66.1
08/18/2010 <10 Acceptable 77.198 13.08 8.82 9.1 72.7
07/22/2010 <10 Acceptable 78.962 13.4 20.76 16.2 76
06/16/2010 <10 Acceptable 70.808 9.29 2.15 41.3 69.7
05/22/2010 41 Acceptable 60.188 13.05 3.68 88 80.7
10/19/2009 10 Acceptable 56.534 12.46 1.71 57.5 82.6
09/15/2009 <10 Acceptable 72.05 13.02 1.46 36.6 66
08/21/2009 <10 Acceptable 79.628 8.85 4.53 51.5 72.8
07/29/2009 <10 Acceptable 76.766 6.11 2.99 18.2 78.7
06/23/2009 <10 Acceptable 70.214 1.41 0.85 42 88.6
06/06/2009 10 Acceptable n/a n/a n/a n/a n/a
05/13/2009 10 Acceptable 60.17 6.08 1.72 78.7 80.1
10/21/2008 <10 Acceptable 61.772 12.18 1.83 17.9 79.8
10/20/2008 10 Acceptable 62.798 16.89 1.33 21.1 72.2
10/20/2008 20 Acceptable 62.024 13.31 1.51 19.8 78.7
10/19/2008 20 Acceptable 62.762 16.9 1.64 28.7 78.4
09/23/2008 <10 Acceptable 70.2 12.49 1.33 11.3 76.3
08/19/2008 10 Acceptable 77.2 8.3 2.2 29.5 83.5
07/14/2008 15 Acceptable 74.588 11.85 2.88 15.5 76.7
07/02/2008 15 Acceptable 75.11 10.89 4.31 24.1 82.2
06/24/2008 13 Acceptable 72.248 10.06 1.93 24.7 76.7
05/19/2008 20 Acceptable 59.9558 5.985 1.305 36.15 93.15
09/06/2007 18 Acceptable 74.642 12.13 2.41 16.4 74.5
08/16/2007 <10 Acceptable 78.386 11.47 2.79 36.2 76.1
07/11/2007 <10 Acceptable 75.533 12.61 6.76 19.05 89.6
06/18/2007 3 Acceptable n/a n/a n/a n/a n/a
05/23/2007 6 Acceptable 63.059 4.165 1.07 81 91
04/18/2007 103 Beach Advisory 43.412 0.39 0.4 95 99.5
12/13/2006 40 Acceptable 45.014 2.58 1.13 11.9 95.6
11/10/2006 22 Acceptable 52.502 0.84 1.77 54.7 94.9
10/18/2006 12 Acceptable 63.302 10.19 2.53 10.6 81.6
09/26/2006 23 Acceptable 69.746 9.14 1.22 n/a 86.5

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
This sewage treatment plant treats sewage from much of the western side of Westchester County. The area has boating, kayaking and fishing.

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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