Sewer Line Smoke Testing

The City of Fredericksburg performs a "Smoke Test" survey to assist inspection crews in locating breaks and defects in our sanitary sewer system. The information received from this testing helps us to improve sewer services.


What is a smoke test?

Smoke testing is the process of forcing smoke filled air into the sewer system. A liquid smoke product is used during the process. At any break or defect in the sanitary sewer system, the smoke will rise from the ground, alerting inspection crews of an issue at that location. 


What happens before, during, and after the smoke test?

  • Inspection crews will be going door-to-door, notifying residents and business owners of the process and handing out contact information prior to the testing. It is advisable for the home or business owner to pour a gallon of water into each floor drain prior to the testing.
  • While the testing is taking place, City of Fredericksburg Water/Wastewater Division crew members will identify breaks and defects in the sewer system where smoke escapes through them.
  • When the testing is complete, residents and business owners will be notified if any problems have been identified that need to be addressed.

Do I need to do anything before, during, or after the smoke test?

  • It is advisable for the home or business owner to pour a gallon of water into each floor drain prior to the testing.
  • If there is any individual in your home or business who has respiratory problems and is immobile, please notify us at (830)990-2070 prior to testing.
  • Smoke from the testing should not enter your home or business unless you have defective plumbing or dried up drain traps. If smoke enters your home or business during the testing, there is good reason to assume that dangerous sewer gases may also be entering your home or business. You should evacuate immediately and notify our work crews.
  • If you are not home during the testing and discover smoke when you return, please call us at (830)997-8080.

What are the ingredients of the smoke? Is it poisonous?

Is the smoke harmful?

The smoke is non-toxic, however, if smoke enters your home or business, it is an indication that harmful sewer gases are also entering through a plumbing defect. It is recommended that any elderly or disabled person is not left unattended during this testing process. Pets should also be monitored during the testing.

Will the testing interrupt my sewer service?

Sewer service will not be interrupted during the testing.

Who should I contact if I have additional questions or concerns?

For more information regarding this process or any questions, please contact Dennis Durst, Interim Water/Wastewater Superintendent, at (830)990-2070.