Smoke Testing, or sometimes referred to as Vapor Testing, is an extremely efficient and cost effective investigative method of pinpointing stormwater cross-connections into sanitary sewer systems.  The general approach consists of blowing a low pressure, non-toxic, non-staining, smoke or vapor into the sanitary sewer system.  The result is such that the smoke will fill all sanitary pipes connected to the main, along with any stormwater cross connections that may be present.  Crews then document all exiting sources of smoke via video and picture images.  The final report consists of all video, photos, and detailed test results.  Typical sources of I&I that we find in our smoke testing programs are:

  • Catch basins connected to the sanitary sewer
  • Below grade sewer clean-outs
  • Roof leaders and drain tile cross connected
  • Sump pumps cross connected
  • Detention Pond Overflows
  • Leaky manhole chimneys and frames

Many of SFE Global’s smoke testing programs have immediately located major sources of direct stormwater inflow.  Many feel that smoke testing your sanitary sewers in an effort to locate sources of I&I is the best “bang for the buck” when it comes to assessment options.  Smoke testing typically goes hand in hand with sewer flow monitoring, CCTV, and manhole inspections programs.  This service gives immediate visual results and usually allows Cities to make quick decisions on rehabilitation efforts, sometimes resulting in a dramatic decrease in I&I.

So when is the best time to perform smoke testing?  The vast majority of our smoke testing programs will start in spring and into the summer months.  Best results are achieved when ground water is down and there’s limited chances of high wind and rain.  Poor weather and high ground water tend to limit the effectiveness of your smoke testing program.

Please contact SFE Global for more information on how sewer smoke testing can help you locate your sources of inflow and infiltration.  Mike Lemmen can be reached directly at, via telephone at 1.866.332.9876, or through our website contact page at