Sewer Testing

Sewer testing is happening in Saint Paul this summer. 

We test our sewers by putting a simulated smoke into the sewers to find leaks and faulty connections. 

Where and when we are testing our sewers:

We will be doing our yearly sewer tests this summer from June 1 through July 31 in the following area.

The second half of the sewer testing project will be from July 24 through end of September in the following area.

How and why we test our sewers:

Finding leaks in our sewers is essential to keep our sewers working well, to protect our asset, reduce costs, and keep our soil and water clean.  

We test our sewers by putting a simulated smoke into the sewers to find leaks and faulty connections. The test lasts about 30 minutes, which may be seen coming from manhole covers, storm drains, roof vents, and building foundations.

How the test impacts you:

The simulated smoke is not expected to enter your home, but if it does, don’t be alarmed – simply open doors and windows to ventilate the area. The simulated smoke should clear out quickly. The simulated smoke is safe, but may cause some irritation.

What you need to do:

If you see the simulated smoke in your home, there is no reason to be alarmed, but please call us at 651-238-0572.

We work with police and fire departments while testing. We want to make sure everyone is aware of the testing to limit the false alarms.  

Check out this map  to find out if and when your area will be tested. We will also call you and leave a door hanger prior to the test happening in your neighborhood.

Need more info or have questions?

Call us at 651-238-0572. 

Need this information Translated?

For Hmong translation, please click here In Hmong Language
For Spanish translation, please click here In Spanish Language

Or call us at 651-266-6100

The Details

In-depth information about Sewer Testing.

The Process:

  • Simulated smoke will be injected into the sewer system. As a result simulated smoke may be seen coming from manhole covers, storm drains, roof vents, and building foundations.
  • The sewer safety test will last approximately 30 minutes.
  • Inspection crews will not need to enter buildings, unless to gain access to building rooftops.
  • Faucets and bathroom facilities can still be used during smoke testing.

Tips to prevent simulated smoke from entering your building (complete prior to test):

  • Run water faucets for a few seconds in unused sinks, tubs, and drains to fill fixture traps.
  • Pour water into each floor drain (at least 1 gallon)
  • If you have defective plumbing (i.e. no trap), you should consult with a licensed plumber.

If you notice simulated smoke in your building:

  • Do NOT become alarmed
  • Open doors and windows to ventilate the premises to clear smoke.
  • Contact the Sewer Testing Crew, @ (651) 238-0572.
  • Simulated smoke will not stain walls or furniture; nor will it leave a residue.
  • ​Contact a licensed plumber in the near future to find out if you have a problem with your sewer connection.

Safety and Health Concerns:

  • There is NO danger in the process. The simulated smoke will not cause a fire or explosion.
  • St. Paul Police and Fire Departments have been notified of the sewer safety testing.
  • Simulated smoke is not harmful to your health, but may cause some coughing. Smoke irritation is temporary and should disappear after exposure has ceased. If you do encounter the simulated smoke – avoid unnecessary exposure to it.
  • The smoke is not harmful to pets, but it would be a good idea to leave windows partially open for ventilation, should any smoke enter the building. If you have proper plumbing connections and all of the drain traps have water in them, there should not be any problem.
  • If there is an individual in your building, business, or residence who has respiratory problems and/or mobility limitations please contact us at 651-238-0572, before June 1, 2017.
  • A copy of Material Safety Data Sheet (MSDS) for the simulated smoke can be found at 

Building Managers/ Property Owners/ Residents Information:

1. For those located within the Sewer Safety Testing Project Area: Access to building roof tops may be needed for city and/or contracted staff to document the simulated smoke emissions from buildings (City Legislative Code 76.13).

2. For those located within the Mailing Area (see enclosed map): Before June 1, please fill unused fixture traps and floor drains with water (at least 1 gallon for each).


2017 Testing Information and Area Map - Area 1

SEH, a contractor working for the Sewer Utility, will test a portion of the City's sanitary sewer system. Please see the attached project area map and sewer testing notices that has been mailed to residents and property owners.

The following means of communication will be employed:

  1. Initial Public Notice - By Mail (includes: Notice, and Project Area Map, see attachments)
  2. Automated Phone Call to residents/property owners notifying them of the mailing and public informational meeting.
  3. Door Hanger Placement (to be placed approximately two to three days before testing occurs).
  4. Automated Phone Call - A second automated phone call is to be placed 24 to 48 hours prior to smoke testing work beginning. Also, close coordination with the St. Paul Fire Department is also essential to address the potential for false fire alarms. They will be updated on a regular basis.

The Sewer Testing Crew chief can be contacted @ 651-238-0572 if any simulated smoke is reported in a building.


For further information on the LiquiSmoke product used in testing our sewers, as well as material testing results regarding exposure and health please visit: