Project Contact:

  • Mr. Steve Hunt, Project Manager
  • 573.874.7264

Columbia’s sanitary sewer collection system is a combination of privately and publicly owned and maintained infrastructure. The publicly owned and operated portion of the system consists of approximately 670 miles of sewer lines, 16,000 manholes, 25 pump stations and the wastewater treatment plant. The privately owned portion of the system consists of an estimated 600 miles of service laterals and 10 miles of private common collector (PCC) sewers, 11 miles of private sewers owned and maintained by the University of Missouri, and several satellite sewer systems owned and maintained by the Boone County Regional Sewer District.

As part of the 2004 Sewer Master Plan, the City’s sanitary sewer collection system was divided into 64 drainage basins for flow monitoring and modeling purposes.  Currently, 57 of the 64 sanitary sewer drainage basins experience peak wet weather to average dry weather flows greater than 3:1. These wet weather flows have led to surcharging of the sewers, basement backups and operational problems at the wastewater treatment plant. The goals of the System-Wide Inflow and Infiltration Reduction Program is to reduce the amount of I/I in the drainage basins to less than 3:1 peaks, and eliminate all wet weather related basement backups and sanitary sewer overflows.

TREKK Design Group was contracted by the City to conduct manhole inspections, sewer smoke testing and building inspections throughout the drainage basins. Additional items include the inspection of 20 percent of the service laterals and sewer mains, flow monitoring, hydraulic modeling and rehabilitation design of both public and private sector I/I sources. Twenty-four basins have been identified for I/I reduction. TREKK has completed four of the basins and is currently working in Priority 5 & 6 basins.

TREKK has completed more than 7,000 manhole inspections, 5,600 building inspections and smoke tested more than 250,000 linear feet of sewer. Both private I/I abatement and public rehabilitation have been completed in the Priority 1 basin, and are currently being completed in Priority 2 through 4 basins.

It is estimated that the reduction in I/I over the 24 basins will save more than $72 million in wet weather and relief sewer improvements.

Sewer Modeling:

Sewer modeling is where all the information obtained from the SSES is compiled and analyzed so that City staff can plan the rehabilitation projects for upcoming years on a priority basis. The success of this project is entirely dependent upon individual property owner participation. The more individual participation we have, the more accurate our picture of the sanitary sewer system becomes.

Who is eligible for reimbursement under the Inflow and Infiltration Program?

Anyone with property in the study area that is an owner-occupied residence having three (3) units or less, that was constructed before 1996, and has a private inflow and infiltration source listed in the table in section 22-217.3(b) of the City Ordinance.


For more information about the program contact:

City of Columbia Missouri – Sanitary Sewer Utility