City of Madison water and sewer department officials will begin smoke testing the sanitary sewer system in September.

A non-toxic, non-staining white smoke will be blown into manholes and the sewer system throughout the city beginning Sept. 1, a news release said. Testing is expected to be completed by Oct. 2, weather permitting.

Testing will take place on weekdays between 8 a.m. and 6 p.m., providing there is no significant rainfall for 24-hour periods or high winds prior to the scheduled testing. Testing will not be performed on the weekends, the release said.

The smoke testing will help to identify leaks in the system that may cause problems leading to sewer overflows. Leaks in the sewers, house laterals and plumbing that would allow groundwater or rainwater into the system are identifed by visible smoke leading from the system.

City residents may see smoke coming out of manholes, inlets or out of the ground. Smoke may also be seen coming from building gutters, downspouts and plumbing vents on roofs, the release said.

Smoke should not enter homes, the release said. If smoke does enter a home, officials say it could mean a drain trap is dry or there is a plumbing defect.

They suggest property owners pour a few glasses of water into each floor drain, sink, bathtub or other fixtures with a drain, the release said. The water should properly fill the drain trap and prevent smoke from entering the home.

Any smoke will disappear without leaving any residue or odor, the release said. It will go away quicker if a window or door is opened in the affected area.

If a resident notices smoke entering their home contact a member of the testing team stationed along the street for immediate attention or call the City of Madison at (812) 265-8312.

The smoke used in the project is manufactured for testing purposes and has been found to be harmless, the release said. The smoke being used is chemically generated, but it is non-toxic, non-staining, has no odor and creates no fire hazard. The smoke will be white in color.

As a precaution, City of Madison officials recommends any person with respiratory sensitivity to take necessary precautions and avoid exposure.

Material Safety Data Sheets of the product are available upon request from field personnel conducting the tests and from the City of Madison website at

The city had contracted with Commonwealth Engineers Inc. of Indianapolis to assist with the testing.