Sources of Inflow & Infiltration

Municipal Sanitary Sewer Systems

  • Perforated manhole covers (pickholes included). Manholes located near curb and/or gutter are highly susceptible to I/I.
  • Broken or Cracked Manhole Frames
  • Wall seepage through mortar between bricks or concrete block, base of manhole frame, joints of precast concrete riser sections, lift holes, broken ladder rungs.
  • Deteriorated channels and benches.

Sewer Pipes
  • Structural defects such as: pipe wall cracks and fractures, holes, broken collapsing pipes and pipe shear breaks.
  • Pipe joints which are misaligned, separated, open, deflected, offset, chipped or cracked.
  • Protruding plumber’s taps which also can prevent or obstruct maintenance activities and sewage flow in the main line.
  • Root masses
  • Cross-connections
  • Stormwater sewer connection

Private Sanitary Sewer System (Service Connection)
  • Cleanouts
  • Broken risers and caps
  • Used as a floor and/or area drain
  • Sewer Pipes
  • Same as municipal sewers
  • Cross-connections
    • Roof leaders tied into service connection sewer
    • Driveway and/or area drain tied into service connection sewer
    • Building foundation drain tied into service connection sewer
    • Sump pump discharge into service connection sewer