Sanitary Sewer Smoke Testing

Smoke testing is a way to locate openings in the sewer system that allow rainwater runoff to enter and can cause inconvenient and expensive sanitary sewer backups. Air combined with non-toxic smoke is forced into sewer lines to disclose the location of leaks and connections. Smoke can be seen coming up out of the ground where there are defects in the lines. Smoke testing also identifies roof drains, patio drains and footing drains that are connected to the sewer system.

2022 Locations 

The City of Naperville contracted with RJN Group, Inc. of Wheaton to perform smoke testing, which began the week of June 20. Work is expected to be completed in late October, pending weather or unforeseen circumstances. If you live in an area that will be affected by smoke testing, you can expect to receive a notification letter in the mail by the week of June 13. Additional notification will be provided by door hanger cards between 24 and 72 hours before testing in your area is expected to begin. Signs will be posted at highly visible intersections when crews are testing nearby. 

View an overall map of the smoke testing area

What to Expect

Smoke will not enter buildings unless there is defective plumbing or dried-up drain traps. It is expected – and normal – for smoke to come out of the sewer vent stack on the roof of a building during the test.

The smoke is non-toxic, creates no fire hazard, leaves no residue, dissipates quickly and is harmless; however, those with respiratory issues may wish to take extra precautions, such as leaving the area for a few hours until testing is complete. 

What You May See

Current Activity

July 15, 2022: RJN Group is actively conducting smoke testing when weather permits. Testing is expected to take place through the end of October. 

Timeline and Location

Smoke testing began the week of June 20 and is expected to be completed by the end of October, weather permitting.

2022 Smoke Testing Map - Central

2022 Smoke Testing Map - Southeast

What To Do if You See Smoke

You should always feel free to call 9-1-1 in an emergency. If you believe smoke is entering your home from the smoke testing, simply open a window and the smoke will dissipate quickly. Also notify the crew that is conducting the  tests by contacting a member of the crew on the street. 

The smoke is non-toxic, creates no fire hazard, leaves no residue, dissipates quickly and is harmless; however, those with respiratory issues may wish to take extra precautions such as leaving the home for a few hours until testing is complete. 

Additional Information

Read our Smoke Testing Q&A for answers to frequently asked questions about smoke testing studies. 

Learn more about our contractors at the RJN Group website.