Smoke Testing

Starting June 1, 2020 through September 18, 2020, inspection crews will be conducting a physical survey of a portion of the City of Temple’s sanitary sewer system using smoke testing to locate obstructions and defects in the sewer system. This study will involve the opening of manholes in the streets and easements. The smoke that you see coming from the vent stacks on houses or holes in the ground is NON-TOXIC AND CREATES NO FIRE HAZARD. The smoke should not enter your home unless you have defective plumbing or dried up drain traps. To prevent smoke from entering your home, please pour water in seldom used sink drains, bathtubs, and toilets, to fill the trap. If smoke does enter your home, please contact a member of the smoke testing crew, who should be in your neighborhood, so that testing can be halted. Although harmless, the smoke can be inconvenient. If smoke does enter your home, the potential exists for dangerous sewer gases to enter your home also. A licensed plumber can correct such problems. Drain traps should always be filled with water to prevent sewer gases or odors from entering the building. 

Some sewer lines and manholes may be located on the backyard easement property line. Whenever these lines require investigation, members of the inspection crews will need access to the easements for sewer lines and manholes. Please temporarily secure your pets away from these locations. RJN field personnel are uniformed and carry identification badges. Homeowners do not need to be home and AT NO TIME WILL FIELD CREWS HAVE TO ENTER YOUR BUSINESS OR RESIDENCE. Working hours for crews in your area will be MONDAY THROUGH FRIDAY FROM 8:00 A.M. TO 5:00 P.M. Your cooperation is appreciated. The information gained from this study will be used to improve your sewer services. 

COVID-19: RJN field crews will be wearing masks and gloves and will follow the recommended precautions by the CDC. 

If you have any questions or would like more information, visit, contact RJN Group, Inc. at 

Bird Creek Sewer Basin Smoke Test Area

Additional Information

It's OK if smoke is coming out of the building vents.   

The smoke should not enter your home unless you have defective plumbing or dried up drain traps.  If it does, please pour a small amount of water in seldom-used drains to fill the trap and contact RJN staff working in the area.  Contact information was also provided on the notifications mailed to your home or the door tag notification.       

View the educational video below for more information.


What is the benefit to my community?

Smoke testing is one technique used to identify areas where unnecessary groundwater or rainfall is entering the sewer system which can cause basement backups, overflows, and higher costs for treatment.  

What is smoke testing?

Using odorless, non-toxic smoke candles and high capacity blowers, smoke is forced through the sewer pipes.  As shown in the video, the blowers are placed on top of manholes.  Anywhere the smoke exits, there is potential for rain or groundwater to seep into the sewer system.

How will I know when smoke testing will be performed in my neighborhood?

At least 24 hours before smoke testing is scheduled to start, RJN will place door hangers on the front door of every building where testing will be conducted.  Signs will be prominently displayed on the street when smoke testing is in progress. 

How are RJN crews recognizable?

RJN staff will carry identification badges and wear apparel that is clearly marked with RJN logos. RJN signage will also be visible on all vehicles.

Is the smoke hazardous?

Not at all. The smoke that comes out of the vent stacks on houses or holes in the ground is non-toxic, harmless, and has no odor. It does not create a fire hazard.

Do I need to do anything to prepare for smoke testing?

Drain traps should always be filled with water to prevent sewer gases from entering the building.  About 3 cups of water should be poured in floor and sink drains, filling the traps to prevent smoke from entering the home. If smoke does enter, the resident should consult a licensed plumber.  If harmless smoke can enter through faulty plumbing, the potential exists for dangerous sewer gases to also enter the home. Should smoke enter your building or structure, contact a member of the smoke testing crew working in the area.

What if smoke shows in my yard or driveway?

This could mean that there is a drain on the property that is connected to the sewer lateral or that the lateral has breaks or cracks in the pipe that cause drain runoff after it has percolated into the soil.

Do I need to be home when smoke testing is performed?

Homeowners do not need to be home and at no time will field crews need to enter residences or buildings.  Smoke testing crews will be noticeable documenting the testing, taking photos, and measuring distances.

What if a test yields no smoke defects?

Obviously, if the sanitary sewer line and the lateral are in good condition, and there are no drainage  facilities connected to them, the smoke has no place to go other than up the house vent stack, as it is supposed to.  However, sometimes the smoke doesn't appear at all even though there is a defect. RJN crews are trained to identify these "suspect" situations and may recommend dye testing to conclusively determine whether the suspect is positive or negative. But this is a subject for its own set of Q&As.


If you have questions or concerns regarding smoke testing, contact our Utility Department at 254-298-5611