« Is there sewage in the Chicago River?

History of combined sewer overflows

The Metropolitan Water Reclamation District of Greater Chicago tracks whenever they release raw sewage in to Chicago area rivers. Since January 1st 2007, raw, untreated sewage has been dumped in to rivers on 660 days.

These occurrences are referred to as combined sewer overflow events, or CSOs.

Note: This data has not been updated since March, 2018 and does not reflect the most recent combined sewer overflow events.

Date # river segments affected # sewage outfall locations
Mar, 01 2018 2 2
Feb, 23 2018 2 10
Feb, 21 2018 6 22
Feb, 20 2018 13 177
Nov, 18 2017 7 53
Nov, 17 2017 4 5
Nov, 16 2017 1 1
Nov, 15 2017 1 1
Oct, 25 2017 1 46
Oct, 24 2017 11 96
Oct, 23 2017 10 102
Oct, 22 2017 1 1
Oct, 19 2017 1 1
Oct, 15 2017 9 102
Oct, 14 2017 16 299
Oct, 12 2017 1 2
Oct, 11 2017 7 17
Oct, 10 2017 3 7
Aug, 27 2017 1 2
Aug, 22 2017 1 1
Aug, 21 2017 1 1
Aug, 03 2017 3 5
Jul, 22 2017 10 76
Jul, 21 2017 10 77
Jul, 20 2017 12 78
Jul, 19 2017 1 1
Jul, 13 2017 1 2
Jul, 12 2017 13 109
Jun, 29 2017 7 23
Jun, 28 2017 1 6
Jun, 23 2017 8 37
Jun, 17 2017 2 2
Jun, 14 2017 10 59
May, 28 2017 2 7
May, 26 2017 5 16
May, 25 2017 1 1
May, 24 2017 3 4
May, 23 2017 3 6
May, 18 2017 1 1
May, 16 2017 1 1
May, 13 2017 1 1
May, 12 2017 1 1
May, 11 2017 1 1
May, 10 2017 6 19
May, 02 2017 1 1
May, 01 2017 7 41
Apr, 30 2017 11 132
Apr, 29 2017 15 124
Apr, 16 2017 2 3
Apr, 10 2017 5 7
Apr, 06 2017 9 37
Apr, 05 2017 8 25
Mar, 31 2017 2 5
Mar, 30 2017 16 135
Mar, 26 2017 1 4
Mar, 25 2017 2 4
Mar, 01 2017 2 2
Feb, 28 2017 7 17
Feb, 24 2017 1 2
Feb, 23 2017 1 1
Feb, 07 2017 2 4
Jan, 20 2017 5 24
Jan, 19 2017 3 5
Jan, 18 2017 1 1
Jan, 17 2017 11 51
Jan, 16 2017 1 4
Jan, 11 2017 6 18
Jan, 10 2017 3 7
Dec, 26 2016 1 1
Nov, 30 2016 2 2
Nov, 29 2016 2 3
Nov, 28 2016 4 26
Nov, 24 2016 1 1
Nov, 23 2016 1 2
Nov, 18 2016 1 2
Nov, 09 2016 1 1
Nov, 02 2016 1 3
Oct, 31 2016 1 1
Oct, 30 2016 2 2
Oct, 26 2016 5 16
Oct, 24 2016 1 1
Oct, 17 2016 1 1
Oct, 16 2016 3 5
Oct, 06 2016 1 1
Oct, 01 2016 4 30
Sep, 28 2016 2 2
Sep, 21 2016 4 4
Sep, 08 2016 1 1
Sep, 07 2016 3 3
Aug, 30 2016 7 27
Aug, 29 2016 2 6
Aug, 27 2016 3 3
Aug, 20 2016 11 38
Aug, 19 2016 3 4
Aug, 18 2016 8 11
Aug, 15 2016 2 2
Aug, 13 2016 3 12
Aug, 12 2016 10 45
Jul, 25 2016 1 2
Jul, 24 2016 11 108
Jul, 23 2016 13 89
Jul, 21 2016 5 10
Jul, 18 2016 3 4
Jul, 17 2016 2 3
Jul, 13 2016 2 3
Jul, 07 2016 3 8
Jul, 06 2016 5 12
Jun, 23 2016 1 1
Jun, 22 2016 11 22
Jun, 15 2016 1 1
Jun, 02 2016 4 8
Jun, 01 2016 1 1
May, 31 2016 5 5
May, 27 2016 9 22
May, 26 2016 4 28
May, 25 2016 12 127
May, 14 2016 1 1
May, 13 2016 1 1
May, 12 2016 1 1
May, 10 2016 1 1
May, 09 2016 1 1
May, 02 2016 1 1
May, 01 2016 1 1
Apr, 30 2016 1 1
Apr, 28 2016 1 1
Mar, 24 2016 4 6
Mar, 15 2016 1 1
Feb, 03 2016 2 3
Feb, 02 2016 6 6
Jan, 25 2016 1 1
Jan, 14 2016 1 1
Jan, 09 2016 1 1
Jan, 08 2016 3 5
Dec, 30 2015 1 1
Dec, 29 2015 3 3
Dec, 28 2015 3 3
Dec, 23 2015 4 8
Dec, 14 2015 2 3
Dec, 13 2015 1 1
Nov, 27 2015 5 7
Nov, 21 2015 1 1
Nov, 18 2015 1 1
Nov, 17 2015 1 1
Oct, 24 2015 5 15
Sep, 19 2015 15 69
Sep, 18 2015 14 83
Sep, 17 2015 1 1
Sep, 12 2015 1 1
Sep, 09 2015 1 1
Sep, 08 2015 8 15
Aug, 19 2015 6 6
Aug, 18 2015 12 193
Aug, 17 2015 9 132
Aug, 16 2015 1 28
Aug, 15 2015 1 1
Aug, 06 2015 2 2
Aug, 04 2015 1 1
Aug, 03 2015 6 7
Aug, 02 2015 6 65
Aug, 01 2015 1 8
Jul, 13 2015 2 4
Jul, 07 2015 1 1
Jun, 22 2015 1 1
Jun, 20 2015 2 2
Jun, 19 2015 3 3
Jun, 18 2015 6 45
Jun, 17 2015 7 31
Jun, 16 2015 13 80
Jun, 15 2015 19 1324
Jun, 14 2015 11 54
Jun, 13 2015 2 34
Jun, 08 2015 1 1
May, 09 2015 1 1
May, 05 2015 2 2
Apr, 10 2015 1 1
Apr, 09 2015 8 33
Nov, 24 2014 1 1
Nov, 22 2014 1 1
Oct, 15 2014 7 17
Oct, 14 2014 8 19
Oct, 04 2014 1 1
Oct, 03 2014 4 4
Sep, 21 2014 1 1
Sep, 11 2014 2 4
Sep, 10 2014 7 20
Aug, 26 2014 6 16
Aug, 25 2014 7 32
Aug, 24 2014 5 8
Aug, 23 2014 11 43
Aug, 22 2014 10 35
Aug, 21 2014 3 5
Aug, 20 2014 1 1
Aug, 12 2014 1 1
Aug, 05 2014 11 48
Aug, 04 2014 9 45
Jul, 25 2014 1 5
Jul, 23 2014 1 1
Jul, 22 2014 1 1
Jul, 16 2014 1 1
Jul, 15 2014 1 2
Jul, 14 2014 8 13
Jul, 13 2014 15 60
Jul, 12 2014 13 61
Jul, 08 2014 1 1
Jul, 07 2014 2 2
Jul, 02 2014 6 18
Jul, 01 2014 14 49
Jun, 30 2014 10 39
Jun, 25 2014 6 10
Jun, 24 2014 11 58
Jun, 23 2014 5 7
Jun, 22 2014 6 6
Jun, 21 2014 12 75
Jun, 20 2014 3 5
Jun, 19 2014 3 15
Jun, 18 2014 2 2
Jun, 11 2014 2 2
Jun, 10 2014 1 1
May, 28 2014 1 1
May, 21 2014 4 11
May, 20 2014 7 17
May, 15 2014 2 4
May, 13 2014 13 34
May, 12 2014 9 29
May, 11 2014 9 25
May, 10 2014 2 2
May, 09 2014 8 40
Apr, 29 2014 1 2
Apr, 09 2014 1 1
Apr, 04 2014 1 3
Apr, 03 2014 9 14
Mar, 12 2014 1 1
Feb, 22 2014 1 1
Feb, 21 2014 11 33
Feb, 20 2014 15 63
Jan, 26 2014 1 1
Jan, 25 2014 1 1
Jan, 14 2014 1 1
Jan, 13 2014 2 2
Jan, 12 2014 2 3
Jan, 11 2014 9 32
Jan, 10 2014 9 25
Jan, 03 2014 1 2
Dec, 20 2013 1 3
Dec, 19 2013 1 3
Dec, 15 2013 1 1
Dec, 14 2013 1 1
Dec, 13 2013 1 1
Dec, 12 2013 1 1
Dec, 11 2013 1 1
Dec, 10 2013 1 1
Dec, 09 2013 1 1
Dec, 08 2013 1 1
Dec, 07 2013 1 1
Dec, 06 2013 1 1
Dec, 05 2013 2 2
Dec, 04 2013 2 2
Dec, 03 2013 2 2
Dec, 02 2013 2 2
Dec, 01 2013 2 2
Nov, 30 2013 2 2
Nov, 29 2013 2 2
Nov, 28 2013 2 2
Nov, 27 2013 2 2
Nov, 26 2013 2 2
Nov, 25 2013 2 2
Nov, 24 2013 2 2
Nov, 23 2013 2 2
Nov, 22 2013 2 2
Nov, 21 2013 2 2
Nov, 20 2013 2 2
Nov, 19 2013 2 2
Nov, 18 2013 2 3
Nov, 17 2013 12 67
Nov, 16 2013 1 1
Nov, 15 2013 1 1
Nov, 14 2013 1 1
Nov, 13 2013 1 1
Nov, 12 2013 1 1
Nov, 11 2013 1 1
Nov, 10 2013 2 2
Nov, 09 2013 2 3
Nov, 08 2013 1 1
Nov, 07 2013 1 1
Nov, 06 2013 2 2
Nov, 05 2013 1 1
Nov, 04 2013 1 1
Nov, 03 2013 1 1
Nov, 02 2013 1 1
Nov, 01 2013 4 5
Oct, 31 2013 12 118
Oct, 30 2013 1 1
Oct, 05 2013 9 33
Sep, 20 2013 2 3
Sep, 19 2013 8 53
Sep, 18 2013 8 71
Sep, 15 2013 1 1
Aug, 31 2013 4 12
Aug, 30 2013 3 6
Aug, 02 2013 3 3
Jul, 31 2013 1 1
Jul, 20 2013 2 2
Jul, 19 2013 2 3
Jul, 15 2013 2 2
Jul, 08 2013 2 2
Jun, 28 2013 4 10
Jun, 27 2013 8 31
Jun, 26 2013 11 59
Jun, 21 2013 2 5
Jun, 12 2013 2 2
Jun, 10 2013 2 2
Jun, 02 2013 8 12
Jun, 01 2013 12 53
May, 31 2013 11 45
May, 30 2013 7 20
May, 29 2013 8 24
May, 28 2013 11 42
May, 23 2013 4 20
May, 22 2013 14 108
May, 21 2013 13 53
May, 20 2013 4 11
May, 10 2013 1 1
May, 09 2013 1 1
Apr, 25 2013 2 3
Apr, 24 2013 6 18
Apr, 23 2013 8 31
Apr, 22 2013 4 8
Apr, 21 2013 8 11
Apr, 20 2013 10 30
Apr, 19 2013 20 58
Apr, 18 2013 24 227
Apr, 17 2013 15 115
Apr, 12 2013 1 2
Apr, 11 2013 12 62
Apr, 10 2013 2 5
Apr, 08 2013 3 4
Mar, 12 2013 5 12
Mar, 11 2013 15 40
Mar, 10 2013 16 67
Jan, 31 2013 2 2
Jan, 30 2013 13 80
Jan, 29 2013 12 60
Jan, 27 2013 1 1
Jan, 11 2013 1 1
Jan, 10 2013 1 1
Dec, 21 2012 4 7
Dec, 20 2012 6 14
Oct, 23 2012 3 5
Sep, 17 2012 1 1
Sep, 04 2012 2 2
Aug, 27 2012 10 28
Aug, 26 2012 13 71
Aug, 13 2012 1 2
Aug, 10 2012 3 4
Aug, 04 2012 5 13
Jul, 26 2012 2 4
Jul, 24 2012 4 12
Jul, 20 2012 1 3
Jul, 19 2012 14 65
Jul, 18 2012 3 5
Jul, 13 2012 2 2
Jul, 01 2012 2 4
May, 08 2012 2 5
May, 07 2012 14 67
May, 06 2012 6 43
May, 04 2012 12 38
May, 03 2012 6 27
Apr, 16 2012 7 20
Apr, 15 2012 11 70
Mar, 24 2012 3 3
Mar, 23 2012 11 60
Mar, 22 2012 1 1
Mar, 08 2012 1 1
Jan, 23 2012 2 2
Dec, 14 2011 2 2
Nov, 27 2011 2 2
Nov, 26 2011 2 2
Nov, 09 2011 8 29
Nov, 08 2011 8 13
Sep, 28 2011 3 9
Sep, 27 2011 4 17
Sep, 26 2011 8 28
Sep, 03 2011 6 12
Aug, 09 2011 1 1
Aug, 08 2011 3 5
Aug, 07 2011 5 17
Aug, 03 2011 4 6
Aug, 02 2011 8 21
Jul, 30 2011 3 6
Jul, 29 2011 14 131
Jul, 28 2011 11 45
Jul, 27 2011 4 9
Jul, 25 2011 2 3
Jul, 24 2011 15 46
Jul, 23 2011 20 149
Jul, 22 2011 8 33
Jul, 20 2011 2 3
Jul, 11 2011 4 6
Jun, 30 2011 1 1
Jun, 20 2011 3 4
Jun, 16 2011 5 9
Jun, 15 2011 5 16
Jun, 12 2011 1 1
Jun, 11 2011 6 9
Jun, 10 2011 16 54
Jun, 09 2011 17 111
Jun, 01 2011 1 1
May, 31 2011 2 2
May, 30 2011 6 21
May, 29 2011 17 175
May, 28 2011 5 11
May, 27 2011 2 4
May, 26 2011 15 61
May, 25 2011 12 115
May, 15 2011 1 4
May, 14 2011 1 1
Apr, 28 2011 4 8
Apr, 27 2011 13 47
Apr, 26 2011 15 83
Apr, 23 2011 7 15
Apr, 22 2011 15 76
Apr, 21 2011 2 7
Apr, 20 2011 8 31
Apr, 19 2011 14 85
Apr, 08 2011 2 4
Mar, 23 2011 1 1
Mar, 22 2011 1 1
Mar, 20 2011 1 1
Mar, 05 2011 8 30
Mar, 04 2011 11 34
Feb, 27 2011 2 3
Feb, 22 2011 1 1
Feb, 21 2011 8 17
Feb, 20 2011 9 18
Jan, 01 2011 3 5
Dec, 31 2010 15 40
Nov, 29 2010 1 1
Nov, 23 2010 5 13
Nov, 22 2010 12 88
Oct, 25 2010 1 1
Oct, 24 2010 1 1
Sep, 03 2010 6 10
Sep, 02 2010 8 63
Aug, 09 2010 2 2
Aug, 08 2010 1 2
Aug, 07 2010 1 1
Aug, 05 2010 4 10
Aug, 04 2010 17 109
Aug, 03 2010 11 30
Aug, 01 2010 1 1
Jul, 31 2010 15 60
Jul, 26 2010 16 95
Jul, 25 2010 18 109
Jul, 24 2010 23 178
Jul, 23 2010 8 36
Jul, 11 2010 3 4
Jul, 08 2010 1 1
Jul, 06 2010 1 1
Jun, 28 2010 5 14
Jun, 27 2010 15 67
Jun, 26 2010 13 76
Jun, 25 2010 5 7
Jun, 24 2010 14 37
Jun, 23 2010 16 130
Jun, 22 2010 2 3
Jun, 21 2010 2 3
Jun, 19 2010 9 21
Jun, 18 2010 8 35
Jun, 16 2010 6 14
Jun, 15 2010 10 41
Jun, 14 2010 1 1
Jun, 06 2010 3 4
Jun, 05 2010 8 23
Jun, 03 2010 3 6
Jun, 02 2010 17 152
Jun, 01 2010 4 7
May, 31 2010 7 25
May, 14 2010 4 37
May, 13 2010 15 156
May, 11 2010 1 1
May, 07 2010 3 3
May, 02 2010 3 5
Apr, 08 2010 2 2
Apr, 07 2010 9 26
Apr, 06 2010 6 61
Apr, 05 2010 10 51
Apr, 04 2010 4 16
Mar, 13 2010 1 1
Mar, 11 2010 1 1
Feb, 10 2010 1 1
Dec, 26 2009 2 9
Dec, 25 2009 15 91
Dec, 24 2009 1 2
Dec, 09 2009 1 1
Nov, 24 2009 2 3
Nov, 02 2009 1 1
Nov, 01 2009 2 2
Oct, 31 2009 8 16
Oct, 30 2009 17 217
Oct, 29 2009 2 3
Oct, 27 2009 1 2
Oct, 26 2009 9 22
Oct, 25 2009 6 11
Oct, 24 2009 6 13
Oct, 23 2009 17 145
Oct, 22 2009 7 19
Sep, 27 2009 1 1
Sep, 20 2009 1 1
Aug, 28 2009 10 32
Aug, 27 2009 11 85
Aug, 26 2009 2 2
Aug, 21 2009 1 2
Aug, 20 2009 1 1
Aug, 19 2009 4 5
Aug, 18 2009 1 1
Aug, 17 2009 9 39
Aug, 16 2009 4 5
Jul, 23 2009 3 6
Jul, 11 2009 3 5
Jun, 25 2009 2 2
Jun, 24 2009 6 37
Jun, 22 2009 2 2
Jun, 21 2009 2 3
Jun, 20 2009 10 26
Jun, 19 2009 14 123
Jun, 18 2009 5 9
Jun, 17 2009 9 26
Jun, 16 2009 12 61
Jun, 11 2009 1 2
Jun, 01 2009 3 4
May, 28 2009 3 3
May, 27 2009 10 21
May, 26 2009 10 20
May, 16 2009 1 1
May, 15 2009 3 3
May, 14 2009 9 24
May, 13 2009 5 14
May, 07 2009 4 21
May, 06 2009 5 11
May, 02 2009 1 1
May, 01 2009 3 5
Apr, 30 2009 13 61
Apr, 28 2009 14 59
Apr, 27 2009 15 65
Apr, 26 2009 5 18
Apr, 25 2009 3 10
Apr, 07 2009 2 4
Apr, 06 2009 4 6
Apr, 01 2009 2 3
Mar, 31 2009 9 13
Mar, 30 2009 1 1
Mar, 29 2009 9 41
Mar, 13 2009 1 1
Mar, 12 2009 3 6
Mar, 11 2009 11 20
Mar, 10 2009 16 117
Mar, 09 2009 13 35
Mar, 08 2009 19 179
Mar, 07 2009 11 88
Feb, 28 2009 2 3
Feb, 27 2009 14 61
Feb, 26 2009 15 96
Feb, 13 2009 1 1
Feb, 12 2009 1 1
Feb, 11 2009 3 3
Dec, 30 2008 1 1
Dec, 29 2008 5 5
Dec, 28 2008 14 34
Dec, 27 2008 19 167
Dec, 13 2008 1 1
Dec, 10 2008 1 1
Dec, 09 2008 6 18
Oct, 08 2008 4 9
Oct, 07 2008 3 8
Sep, 19 2008 1 3
Sep, 18 2008 2 2
Sep, 17 2008 5 11
Sep, 16 2008 12 28
Sep, 15 2008 20 59
Sep, 14 2008 24 121
Sep, 13 2008 22 293
Sep, 08 2008 5 32
Sep, 05 2008 10 19
Sep, 04 2008 19 106
Aug, 23 2008 1 1
Aug, 06 2008 1 1
Aug, 05 2008 10 28
Aug, 04 2008 12 113
Aug, 01 2008 1 2
Jul, 31 2008 1 1
Jul, 22 2008 1 1
Jul, 21 2008 2 4
Jul, 20 2008 10 79
Jul, 19 2008 10 36
Jul, 12 2008 4 11
Jul, 10 2008 1 1
Jul, 08 2008 1 2
Jun, 13 2008 1 2
Jun, 09 2008 9 54
Jun, 08 2008 1 1
Jun, 05 2008 5 16
Jun, 03 2008 3 3
May, 12 2008 1 3
May, 11 2008 8 27
Apr, 25 2008 2 2
Apr, 11 2008 4 7
Apr, 10 2008 8 28
Apr, 08 2008 2 3
Mar, 03 2008 1 1
Feb, 18 2008 5 24
Feb, 17 2008 14 65
Jan, 11 2008 1 2
Jan, 10 2008 5 17
Jan, 09 2008 5 15
Jan, 08 2008 14 72
Nov, 21 2007 1 1
Sep, 25 2007 3 4
Sep, 10 2007 1 1
Aug, 27 2007 3 3
Aug, 26 2007 4 6
Aug, 25 2007 15 49
Aug, 24 2007 18 112
Aug, 23 2007 19 268
Aug, 22 2007 9 52
Aug, 21 2007 2 3
Aug, 20 2007 17 128
Aug, 19 2007 12 91
Aug, 15 2007 3 4
Aug, 09 2007 4 6
Aug, 08 2007 3 5
Aug, 07 2007 8 69
Aug, 06 2007 1 1
Aug, 05 2007 11 44
Jul, 27 2007 3 4
Jul, 26 2007 12 25
Jul, 19 2007 7 28
Jul, 18 2007 11 35
Jul, 10 2007 3 4
Jul, 04 2007 5 8
Jun, 27 2007 5 15
Jun, 26 2007 4 16
Jun, 13 2007 1 1
May, 26 2007 3 4
Apr, 30 2007 2 2
Apr, 28 2007 4 9
Apr, 27 2007 6 12
Apr, 26 2007 13 68
Apr, 25 2007 14 55
Apr, 13 2007 1 1
Apr, 12 2007 5 8
Apr, 11 2007 1 1
Mar, 31 2007 2 2
Mar, 28 2007 1 1
Mar, 22 2007 1 2
Mar, 21 2007 4 5
Mar, 01 2007 9 19
Feb, 25 2007 1 1
Jan, 06 2007 1 3
Jan, 05 2007 7 14
Jan, 04 2007 11 24