Frequently Asked Questions

One of the biggest problems facing the City’s sewer system is inflow and infiltration of rainwater. This can cause high flows and overloading of the piping system and wastewater treatment plant. Smoke testing is used to find potential defects that contribute to this problem.

Smoke testing can also help locate the following:

• The entry location of groundwater or stormwater runoff
• Positive proof that the building or residence is connected to the sewer
• Location of broken sewers due to the settling of the ground
• Missing sewer clean-out caps
• Location of certain illegal connections to a wastewater collection system, such as downspouts, basements, yard drains, industrial drains, and storm sewers

During smoke testing, roadway signs will be posted around the respective neighborhood areas being smoke tested. Uniformed Water Resources field crews are present and available to answer any questions. Field crews will blow air and non-toxic, artificially created smoke into the sanitary sewer system through access points, typically located in manholes. This smoke will travel through the pipes and escape through defects, such as holes and cracks, and will be visible above ground. This smoke will quickly reveal the source of the problem. For instance, if smoke permeates up through a yard, it indicates a break(s) in the sewer line.

Our field crews will locate issues and take photos, if possible. That information is given to our Water Resources Engineering staff, who determine if the defect is in the City system or a private sewer line.

If the defect is on the private sewer line or an unauthorized connection is found, a letter is sent to the resident to let them know what has been found.

Any repair costs to private sewer lines are the responsibility of the owner. Defects on the City piping system are repaired by City field crews

Smoke testing is the most efficient and cost-effective way to identify where rainwater is entering the public sewer system and where the sewer system needs repairs or improvements. Smoke testing will also identify any plumbing leaks that customers have on their private lines.

Elimination or reduction of this excess water will help reduce sewer overflows and the cost of sewer treatment. Overall, smoke testing helps utilities locate these issues and provide quality service to customers.

No, you do not need to be home during this process. Field crews will be monitoring the testing.

Normally, smoke will not enter your home or building during smoke testing.

If your house or business plumbing is compliant with the Building Code and has the proper p-traps on various drain lines, then smoke will not be able to enter the building.

Be sure to periodically run water through each drain in your home to keep the p-traps working to block sewer gases and smoke from smoke testing from entering your home.

If smoke enters your home during testing, note the location of the smoke and open windows to allow smoke to dissipate.

Smoke inside your home may indicate bad plumbing connections or a cracked seal around toilets. Smoke alarms may sound. 

The smoke will dissipate quickly. You may want to get these issues on your private plumbing repaired, as it may allow potentially dangerous sewer gas to enter.

The product used for smoke testing is not harmful to humans or furnishings in the low concentration used.

The “smoke” is not true smoke, but rather a mist containing a large percentage of atmospheric moisture that is highly visible at low concentrations. Exposure to this smoke product may cause minor respiratory irritation, such as coughing, in some people.

The smoke testing will not stain or harm clothing, drapes, or furniture, and will disappear rapidly without leaving an odor.

The smoke used for smoke testing is not harmful to pets. If you have proper plumbing connections and all of the drain p-traps in your home have water in them, then there should not be any problems.

If you have any doubt as to the source of the smoke in your home or yard, call 911 immediately.

The Water Resources Department will also notify 911 and fire services in advance of areas that are being smoke tested.

No. The smoke is made up of a vaporous substance and will not block or damage sewer piping.

Contact Water Resources at 704-282-4601 with questions.