City of Red Wing

City to Conduct Smoke Testing in Sanitary Sewers

Wednesday, May 29 2013 12:00 AM

The City of Red Wing Public Works Department will be conducting smoke testing in the sanitary sewers in the street reconstruction area of 3rd and 4th Street from Cedar to Fulton as well as some streets in the fringes of the project area.  Residents outside this area will not be impacted.  The smoke testing will be done on Tuesday, June 4th depending on weather.  If it rains, the process will be scheduled for the following day.  The purpose for the testing is to identify potential interconnections between the sanitary and storm water sewer systems. 

The smoke testing procedure involves blowing a “smoke-like” substance through a manhole into the sanitary sewer system and observing where it exits into the atmosphere.  This is a common procedure and has been used for more than 30 years.   Smoke will normally be observed coming out of plumbing vents and through rain downspouts in those buildings where the roof drains are connected to the sanitary sewer system.  In the event of an interconnection between the storm and sanitary sewer systems, smoke will also be observed coming out of catch basins, stormwater outfalls and stormwater manholes.   

The smoke will not enter buildings if the sanitary drains are constructed properly and the plumbing traps (the gooseneck section under the drains) are filled with water.  It is recommended that water be run down each drain to make sure the traps are filled.  If smoke is entering into a building; it is likely that potentially hazardous sewer gas is also coming in.  If the smoke cannot be stopped by simply filling the plumbing trap with water, a qualified plumber should make the necessary repairs.

The smoke is not hazardous to people, animals or plants.  It is possible that individuals with sensitive respiratory systems may experience discomfort if a substantial amount of the material is inhaled.  Any smoke will dissipate rapidly and will not leave any odors, residues or films.  Opening windows will help the smoke to clear out.

Additional information has been mailed to residents who will most likely be affected.  Feel free to contact Public Works at (651) 385-3674 if you have any questions.

Click on the links below for additional information on Smoke Testing, or for a map of the affected area.


Smoke Testing Fact Sheet                                            Smoke Testing Map


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