Inflow/Infiltration Reduction Program – Mason City, IA

Inflow/Infiltration Reduction Program


The City of Mason City, Iowa, experienced extremely high sanitary sewer flows and basement backups during flooding events in 2004 and 2008. These events led to the City Council to initiate a five-year comprehensive study of the entire sanitary sewer collection system conducted by WHKS.

The results of the field observations identified priority repairs and helped to guide the Capital Improvement Planning (CIP) budgets for sanitary sewer system maintenance and improvements.  WHKS has provided ongoing design services to the City for sanitary sewer system repair and rehabilitation projects since 2012.

In addition, the City’s GIS system has been significantly updated and was a foundation for proceeding with private sector sump pump inspections.


  • Manhole inspections
  • Flow metering
  • Public involvement
  • Collection system modeling
  • Sanitary sewer repair plans
  • Sewer lining
  • Manhole replacement/rehabilitation
  • Collection system improvement design