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Boston Harbor and Massachusetts Bay
Massachusetts Water Resources Authority

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Water Quality Report Archive

Beach data Harbor and River data
CSO notifications starting in 2020
Cottage Farm CSO notifications
Mass. Bay bacteria data
   
 
AMBIENT MONITORING PLAN MODIFICATIONS
NOV13,2020: Proposed final modifications to the permit-attached Ambient Monitoring Plan. (PDF) JUN5,2020: Interim request for modifications to permit-attached Ambient Monitoring Plan. (PDF)
DEC2010: Modifications to the Ambient Monitoring Plan Approved (PDF) JUL2010: Ambient monitoring plan for the Massachusetts Water Resources Authority effluent outfall, revision 2. (PDF)
JUL2010: Notice and List of changes for public comment. (PDF)  
AMBIENT QUARTERLY MONITORING REPORTS
  2024 2023 2022
2021
Q3 Jul-Sep
Q4 Oct-Dec Q4 Oct-Dec Q4 Oct-Dec Q4 Oct-Dec
2016
2017
2018
2019
 2020
Q4 Oct-Dec Q4 Oct-Dec Q4 Oct-Dec Q4 Oct-Dec Q4 Oct-Dec
2015
2014
2013
2012
2011
Q4 Oct-Dec
2010
2009
2008
 2007
2006
Q4 Oct-Dec
2005
2004
 2003
2002
2001
Q4 Oct-Dec

BEACH DATA
Carson City Point Constitution M Street Malibu Pleasure Bay Tenean Wollaston
2023 2023 2023 2023 2023 2023 2023 2023
2022 2022 2022 2022 2022 2022 2022 2022
2021 2021 2021 2021 2021 2021 2021 2021
2020 2020 2020 2020 2020 2020 2020 2020
2019 2019 2019 2019 2019 2019 2019 2019
2018 2018 2018 2018 2018 2018 2018 2018
2017 2017 2017 2017 2017 2017 2017 2017
2016 2016 2016 2016 2016 2016 2016 2016
2015 2015 2015 2015 2015 2015 2015 2015
2014 2014 2014 2014   2014 2014 2014
2013 2013 2013 2013 2013 2013 2013
2012 2012 2012 2012 2012 2012 2012
2011 2011 2011 2011 2011 2011 2011
2010 2010 2010 2010 2010 2010 2010
2009 2009 2009 2009 2009 2009 2009
2008 2008 2008 2008 2008 2008 2008
2007 2007 2007 2007 2007 2007 2007
2006 2006 2006 2006 2006 2006 2006
2005 2005 2005 2005 2005 2005 2005
2004 2004 2004 2004 2004 2004 2004
2003 2003 2003 2003 2003 2003 2003
2002 2002 2002 2002 2002 2002 2002
2001 2001 2001 2001 2001 2001 2001

 

COMBINED SEWER OVERFLOWS
Summary of CSO Receiving Water Quality Monitoring in Upper Mystic River/Alewife Brook and Charles River
  2021
2020 2019 2018 2017 2016 2015 2014 2013 2011
2010 2009 2008 2007 2006 2005 2004  
COMBINED SEWER OVERFLOW NOTIFICATIONS
All CSO discharges starting in 2020
COMBINED SEWER OVERFLOWS AT COTTAGE FARM CSO
2010-2019
2010 Feb 25 Mar 16 Mar 23 Mar 31 Jun 6 Jul 10 Aug 5 Aug 25
2011 Aug 7 Aug 10 Aug 27 Aug 28 Sep 8 Oct 4    
2012 Jul 18 Sep 19 Oct 29 Dec 27        
2013 Jun 8 Jul 23 Dec 29          
2014 Oct 23 Dec 10            
2015 Jul 10 Sep 30            
2016 Oct 22              
2017 Jun 17 Oct 17            
2018 Jul 17              
2019 Apr 22 Jul 6 Aug 8 Sep 2 Oct 17      

 

CONTINGENCY PLAN EXCEEDANCES
Year Exceedances (Links to PDF Documents)
2024 Annual nearfield chlorophyll (2023)        
2023 Ambient dissolved oxygen (8/11) Ambient dissolved oxygen (9/29) Ambient dissolved oxygen (11/3) Summer nearfield chlorophyll (12/08)  
2022 Alexandrium
(Red tide)(7/5)		 Ambient dissolved oxygen (9/26) Ambient dissolved oxygen (10/7) Ambient
dissolved
oxygen (12/7)		  
2021 Alexandrium
(Red tide)(6/29)		 Ambient dissolved oxygen (9/24) Ambient dissolved
oxygen (11/19)		  
2020 Effluent Nitrogen (1/16)  
2019 Alexandrium
(Red tide)(5/31)		  
2018 No exceedances
2017 Alexandrium (Red tide)(6/20)
2016 Phaeocystis pouchetti (11/17)
2015 Phaeocystis pouchetti (11/13)
2014 Biodiversity (12/5) Phaeocystis pouchetti (9/5)  
2013 Biodiversity (12/13)
2012 Biodiversity (12/14) Phaeocystis pouchetti (10/26) Red tide (5/22)  
2011 Biodiversity (12/15) Red tide (6/10) Biodiversity (1/7)  
2010 Biodiversity (1/7)
2009 Alexandrium (Red tide) (5/18)
2008 Alexandrium (Red tide) (5/16)
2007 Phaeocystis pouchetti (8/17)
2006 Phaeocystis pouchetti (10/25) Chlorophyll Effluent toxicity Red tide
2005 Phaeocystis pouchetti Effluent toxicity Red tide Red tide
2004 Effluent bacteria Phaeocystis pouchetti  
2003 Phaeocystis pouchetti Mussel bioaccumulation  
2002 Mussel bioaccumulation Effluent solids Effluent solids Effluent solids Phaeocystis pouchetti PAH and chlordane
2001 Effluent toxicity Effluent bacteria  
2000 Effluent chlorine Effluent pH Ambient chlorophyll Ambient dissolved oxygen



CONTINGENCY PLAN MODIFICATIONS
Date Modification Letters (Links to PDF Documents)
2/15/18 Final 2017 Contingency Plan threshold modifications
11/13/17 Final Modifications to Phaeocystis and infaunal diversity thresholds
1/3/17 Proposed Modifications to Phaeocystis and infaunal diversity thresholds
11/15/01 Proposed Modifications to dissolved oxygen and Alexandrium thresholds

CONTINGENCY PLAN QUARTERLY REPORTS
     
2024
Ambient Effluent
Quarter 1 Quarter 1
Quarter 2 Quarter 2
   
   
2023
2022
2021
2020
Ambient Effluent Ambient Effluent Ambient Effluent Ambient Effluent
Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1
Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2
Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3
Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4
2019
2018
2017
2016
Ambient Effluent Ambient Effluent Ambient Effluent Ambient Effluent
Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1
Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2
Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3
Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4
2015
2014
2013
2012
Ambient Effluent Ambient Effluent Ambient Effluent Ambient Effluent
Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1
Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2
Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3
Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4
2011
2010
2009
2008
Ambient Effluent Ambient Effluent Ambient Effluent Ambient Effluent
Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1
Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2
Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3
Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4
2007
2006
2005
2004
Ambient Effluent Ambient Effluent Ambient Effluent Ambient Effluent
Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1
Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2
Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3
Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4
2003
2002
2001
  
Ambient Effluent Ambient Effluent Ambient Effluent    
Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1 Quarter 1    
Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2 Quarter 2    
Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3 Quarter 3    
Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4 Quarter 4    

 

DEER ISLAND TREATMENT PLANT MAINTENANCE REPORTS
2021 2022 2023              
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

 

DEER ISLAND TREATMENT PLANT PERFORMANCE REPORTS
2024 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2023 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2022 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2021 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2020 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2019 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2018 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2017 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2016 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2015 Jan Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2014 Jan Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2013 Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2012 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2011 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2010 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2009 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2008 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2007 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2006 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2005 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2004 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2003 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2002 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2001 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2000               Aug Sep Oct Nov Dec

 

DEMAND MANAGEMENT REPORTS
2021 2022 2023 2024            
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

 

DISCHARGE MONITORING: DEER ISLAND TREATMENT PLANT
2024 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2023 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2022 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2021 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2020 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2019 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2018 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2017 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2016 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2015 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2014 Jan Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2013 Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2012 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2011 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2010 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2009 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2008 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2007 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2006 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2005 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2004 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2003 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2002 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2001 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2000                 Sep Oct Nov Dec

DISCHARGE MONITORING - CSO FACILITIES
2024 Jan Feb Mar Apr May Jun Jul          
2023 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2022 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2021 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2020 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2019 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2018 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2017 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2016 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2015 Jan Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2014 Jan Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2013 Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2012 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2011 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2010 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2009 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2008 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2007 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2006 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2005 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2004 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2003 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2002 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2001 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

INFILTRATION & INFLOW REPORTS
2021 2022 2023              
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
  2000
LOCAL LIMITS REPORTS

Analysis of Industrial Pretreatment Local Limits and Proposed Revisions

NPDES Compliance Summary Report
MASSACHUSETTS BAY BACTERIA MONITORING DATA (Excel)

MWRA monitors bacteria at locations surrounding the MWRA outfall and elsewhere in Massachusetts Bay (see station map below). Water samples are analyzed for sewage indicator bacteria: fecal coliform and Enterococcus. Fecal coliform is used by the Massachusetts Division of Marine Fisheries to monitor water quality in shellfish areas. More information is available on the Massachusetts Bay page.
2021 2022 2023 2024          
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
2005 2006 2007 2008 2009 2010


OUTFALL MONITORING OVERVIEW REPORTS
              2022 2021 2020
2019 2018 2017 2016 2015 2014 2013 2012 2011 2010
2009 2008 2007 2006 2005 2004 2003 2002 2001 2000
  1994 1995 1996 1998 1999

Most of these reports are in PDF format, which requires Adobe Acrobat Reader®, a free program available from Adobe Systems. To request a paper copy of any report, please contact the MWRA Environmental Quality Department at 617-788-4601, or e-mail us at web.enquad@mwra.com.
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