Public Utilities contracts with Duke’s to perform smoke testing of the sanitary sewer system periodically. Smoke testing involves introducing non-toxic smoke into the sewer system through manholes and observing if and where the smoke escapes. This process helps identify defects in the system.

Prior to the start of smoke testing, crews leave door hangers at residences and/or businesses where the testing is scheduled to occur.

Before Smoke Testing

Smoke should not enter your home unless defective plumbing or dry drain traps are present. To prevent smoke from entering your home, pour water into any seldom-used sinks, tubs, showers, or floor drains to ensure the traps are full. 

During Smoke Testing

During testing, you may see smoke coming from roof vent stacks, building foundations, manhole covers, storm drains, or holes in the ground. If smoke enters your home, you can open windows to allow ventilation; otherwise, the smoke should dissipate within a few minutes. You are not required to be home during smoke testing.

About the Smoke

The smoke used for smoke testing is non-toxic, non-staining, odorless and does not create a fire hazard. It is safe around humans, pets, food and material goods; however, individuals with severe respiratory issues such as asthma may want to avoid direct exposure as a precaution.