Smoke Testing FAQs

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.

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. If requested by your municipality, smoke testing schedules and sites will also be posted to the Current Project Notices page.

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 three cups of water should be poured into floor and sink drains, filling the traps to prevent smoke from entering the home. While harmless, If smoke does enter the home, residents should immediately consult a licensed plumber. This could indicate faulty plumbing and may potentially allow 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.

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.

What if smoke shows in my yard or driveway?

This could mean a drain on the property 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 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.