Smoke Testing

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The Town annually performs smoke testing in the sewer system to help locate areas where storm water and other surface waters are entering the system and reveal sources of sewer odors. We conduct tests in September using nontoxic smoke in the sewer lines at different locations. Test areas are selected each year and updated online. If we are testing in your area, you will receive a notice in the mail two weeks prior to the test date. Notifications will also be posted on social media prior to the testing. Be sure to follow the Town of Cary on Facebook, Twitter and check your neighborhood Nextdoor for updates. 

See smoke coming from a drain?

Most residents will not see or smell the smoke used during our test. If traces of the smoke or its odor do enter your building, it is an indication that gasses and odors from the sewer may also be entering at other times.

Testing smoke may enter your building if:

  • Vents connected to your building’s sewer pipe are inadequate, defective or improperly installed
  • Pipe, connections and seals of the wastewater drain system in and under your building are damaged, defective, missing plugs or improperly installed
  • Traps under sinks, tubs, basins, showers and other drains are dry, defective, improperly installed or missing. Running water through all sinks, tubs and floor drains upon receipt of testing notification from the Town can reduce the chance of smoke entering due to dry traps under sinks, tubs, basins, showers and other drains.

What should I do if testing smoke enters my building?

Report the presence of smoke in your building during testing by calling 311 or  (919) 469-4000 outside Cary limits. We recommend that you locate and correct the issue allowing smoke to enter your structure. While we’ll render all possible assistance, the correction of any defects on private property is the responsibility of the property owner.


Call: 311 or (919) 469-4000 outside Cary limits.
Submit a Request


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