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Public Works
350 South 5th Street
RM 203 City Hall
Minneapolis, MN  55415-1390

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Sewer Smoke Testing Questions and Answers

What is smoke testing?

Smoke testing is used to locate cracks, leaks or faulty connections that allow rain water in the sanitary sewer system. During the test, workers send white smoke into the sewer system. The smoke will come out through holes in manhole covers, plumbing vent pipes and other locations where rain water can get into the sewer system.

What should I do to prepare?

Pour a bucket of water down your basement floor drain and any toilets, sinks or showers that have not been used within a month.  This water should fill the traps and reduce the chance of smoke entering your home or business.  Smoke may still enter through missing or broken cleanout caps, or defective plumbing that needs repair. 

Call 612-673-3543 for special notification if you or someone in your home has mobility limitations, respiratory conditions or other health concerns that may be aggravated by the smoke.

Is the smoke safe?

Simulated smoke is non-toxic, but may be an irritant for some people or pets with respiratory conditions.  When possible avoid unnecessary exposure to simulated smoke.
For more information about the product used, consult the SDS and Test Data Explanation.

Why is the testing being done?

The City is working to keep costs down for our customers and protect the environment.  When rain water enters the sanitary sewers, it increases the amount of sewage we need to pay to treat. Also, during intense storms, a large influx of stormwater into the sanitary sewers can overwhelm the system, triggering a combined sewage/stormwater overflow.   The City has done a lot to reduce the chances of these kinds of overflows, but more work is needed.

When will the test be done?

Tests will take place in the late summer and fall. Residents and property owners should receive an informational notice by mail prior to testing.  A second notice will be placed on the front door one-to-three working days before the test. Each test lasts approximately 30 minutes.

What should I do if I detect smoke?

Call 911 if you are not certain that the smoke is a result of the City’s testing. Otherwise open a door or window for ventilation and then contact a crew leader listed on the door hanger notice or 673-3543 to report the smoke. The City’s field crew leaders are available to assist you with venting areas where smoke has gotten into a building and help determine if the smoke is from a dry trap or a plumbing problem.

Will I be charged for this work?

Testing is funded by the sewer utility fees paid by all residents and businesses in the city. You will not be charged additional fees for this work.

Last updated Mar 2, 2020



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