The Capacity, Management, Operation, and Maintenance Program (CMOM) is a requirement of all sanitary sewage collection systems mandated by the Wisconsin Department of Natural Resources (WDNR) to assure that the sewage system is properly managed, operated and maintained at all times; has adequate capacity to convey peak flows; and all reasonable steps are taken to eliminate excess clearwater infiltration and inflow from the collection system.  

How the program works

The CMOM program provides the framework for the City of Madison to effectively manage the sanitary sewer collection system.  The program requires municipalities to establish goals and objectives and provide the City’s plan to reach these goals.  

The CMOM program requires municipalities to shift maintenance from reactive to preventive actions by requiring:

  • Municipalities assess the condition of the sewer system
  • Identify problem areas in the system
  • Detect and report excess Inflow/Infiltration
  • Repair or replace problem sewers

On an annual basis, the City updates the status of City’s goals (length of sewers cleaned, televised, length of sewer replaced and lined, status of Inflow/ Infiltration studies, provide the number of backups, number of Sanitary Sewer Overflows (SSOs).  


The end result for the City customer is a better managed collection system with less clogs and fewer sewer backups. We believe the more proactive we are to responding to sanitary sewer backups and sanitary sewer overflows, the fewer we'll have.  Our aggressive approach supports the few backups we have. Nearly 94 percent of the Sewer Utility’s maintenance activities are planned, rather than reactive.  A few examples of reactive work include the following: responding to sewer breaks, removing a blockage (root obstruction, grease), responding to sewer backups or investigating a sink hole.

Proof: Numbers Support Aggressive Approach

The American Society of Civil Engineers estimates on average, a City Madison's size would have 0.29 backups per mile of sewer. With the national average applied, that would mean Madison should have on average 229 backups per year. However, in 2020, Madison recorded nine backups, which is significantly lower than the national average. Our approach proves, with an aggressive preventative maintenance program, we're able to keep the number of backups significantly lower than what's anticipated with the national average.


The City of Madison has come a long way with its preventative maintenance program. The City used to record significantly higher numbers of backups each year.

Timeline Progress of Backups

  1. 1971-1989

    The City of Madison experienced an average of 255 backups per year.

  2. 1992

    The number of backups increased to a record high of 385. City Engineering reorganized its planned maintenance process from a reactive to a proactive approach.

  3. 1994

    Sanitary sewer backups decreased to 237. 

  4. 1999

    Backup numbers were almost cut in half: 120 backups recorded.

  5. 1999-2001

    Backup numbers plateaued.

  6. 2002

    Number of backups dropped below 100 for the first time.

  7. 2006-2013

    Number of backups recorded were fewer than 50.

  8. 2013-2019

    Number of backups recorded were fewer than 25.

  9. 2020

    Engineering reported seven main backups.