Folsom, CA

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Smoke Testing

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The city has been testing and upgrading our sanitary sewer system over the past 10 years. We are taking action to address damaged pipes, improper private sewer construction, and illegal connections to the sewer that offer an easy route for storm water or other non-wastewater discharges to enter the sanitary sewer collection system. Non-wastewater flows entering the sanitary sewer collection system take up valuable capacity, which could potentially cause raw sewage spills, and cost extra money to treat and convey.

Smoke Testing Program Overview

The city implemented a comprehensive program to evaluate and maintain the sewage system and make repairs as they are discovered. Several different operations are used to evaluate the system, including:

Internal inspection of pipe using video equipment
Visual manhole inspections
Flushing and cleaning of the pipes
Smoke testing for illicit connections

Smoke testing is a simple, cost effective way to locate sewer problems with little disruption to the system or residents. This method tests the city-maintained mainline and the integrity of the laterals. Smoke testing has been used extensively to locate defects in sewer systems nationwide.

When and Where

How It Works

City crews will conduct the smoke testing to locate breaks, defects, and illegal connections in the sanitary sewer system. Smoke testing requires the opening of manholes, which are located in the streets, utility easements and/or alleys.

Once opened, a blower is placed on top of the open manhole, which forces a nontoxic smoke into the system. As the smoke is forced through the sewer lines, it will be forced from any openings or defects in the system, as shown in the diagram above.

The white or gray smoke exiting the system is easily observable by the field crews performing the test, who will log each occurrence. Each of these occurrences will be mapped and analyzed.

Smoke Testing Operation Diagram

Diagram of a smoke testing operation

Important Notes

Field crews will not need to enter your residence. However, should a smoke source be visible on your property, the field crews will likely need to enter the property to investigate and log the source.
The smoke is nontoxic, leaves no residue, and does not create a fire hazard. The smoke has been tested by an independent occupational health laboratory, and all carbon monoxide and carbon dioxide tests were within the OSHA Permissible Exposure Limit (PEL). However, people with respiratory conditions, such as asthma, bronchitis, or emphysema, should be careful when exposed to smoke of any kind. If you have any health concerns, feel free to call us at 916-461-6181.
The smoke will likely not enter your home or business unless defective plumbing exists or drain traps are dry. Please pour approximately one gallon of water down any unused drains in your home. This will help prevent smoke from entering your house via seldom-used drains. If smoke should enter your house, please notify the smoke testing crews that will be working in the immediate vicinity. Please be advised that if smoke enters your house during this test, it is likely that sewer gases are entering, as well. It would be advisable to call a licensed plumber to repair any defective plumbing detected during this project.
Your presence is not required during the tests, and all public safety authorities have been notified of this event. We would appreciate it if you would mention this notice to your neighbors in case they have not received a notice.
If you or anyone you know lives in the test area and are concerned about the possibility of smoke entering your property, or if you have any questions concerning this study, please contact the city at 916-461-6181.