The American Society of Civil Engineers (ASCE) released a second report in the series called Failure to Act.  In the U.S. aging pipes and inadequate capacity (SSOs and CSOs) result in the  discharge of an estimated 900 billion gallons of untreated sewage into surface waters each year.  The ASCE estimated that unreliable water and wastewater infrastructure cost American households and business $21 billion/year.

In Ottawa a significant part of the sewer system is a combined system which means sanitary and storm water goes into the same pipe.  Normally all of this is treated at some level.  But when snow melt or rain volume is high, the treatment plants cannot keep up and the overflow is routed directly into the Rideau Canal or the Ottawa River.

Last year 445,803 m³ of combined sewer overflows (SSOs) and sanitary sewer overflows (SSOs) were reported.  This is higher than in 2010, but under half of the total sewer overflow volume reported five years ago.

• 2011    445,803 m³
• 2010    424,000
• 2009    632,000
• 2008    843,000
• 2007    730,000
• 2006 1,090,000

The City of Ottawa has a plan to mitigate the impact of combined sewer overflows into the Ottawa River including real time monitoring and control, building storage capacity to hold overflows until there is capacity to treat the sewage, and continuing sewer separation projects.  With the current funding framework, it is expected that the planned separation work will be completed in approximately 25 years.

Over the next decade the average household water and sewer bill is expected to rise from $636 a year now to $1,045. The rate increases and borrowing of additional $460 million will raise $2.1 billion for maintaining the system.  But this is short of the estimated $2.7 billion that is required, leaving a $600-million gap.