Smoke Testing in Sewers

Smoke Testing is used to detect issues in the sewer. The smoke is non-toxic and non-hazardous and is manufactured specifically for this purpose.

Posted: August 31st, 2018 3:44 PM

Last Updated: January 20th, 2021 8:02 PM

Smoke Testing is used to detect storm water inflow sources such as roof downspouts, driveway drains, area and yard drains, foundation drains and storm water drainage system cross connections. It can also detect structural deterioration and leaking joints in the sanitary sewer collection system and within the private sewer laterals. Smoke testing is one of the most efficient method of locating sources of I/I within sewered areas.

The smoke is non-toxic and non-hazardous and is manufactured specifically for this purpose. It leaves no residuals or stains, and has no effects on plants or animals. The smoke should not enter your home, but if it does, it will have a distinct odor and should only last a few minutes with proper ventilation. Please note, all plumbing fixture drain traps must be filled with water prior to smoke testing.

The smoke is distributed using blowers into manholes and travels through the sanitary sewers and escapes through any connections, defects, cracks, leaks, etc. This quickly reveals sources of infiltration and inflow (I/I) within the testing area from sanitary sewer laterals, cleanouts and roof downspouts. It is not uncommon to see smoke coming out of the grass, wooded areas, utility boxes or cracks in pavements. All smoking sources are documented by a written report and pictures.

Deficiencies will occur in the City's system and in private properties. If smoke sources are found on private properties, a letter is provided to the property owner explaining the deficiencies found and allowing the property owner a specific deadline for corrections of deficiencies. Often times, deficiencies can be easy fixes, such as disconnecting downspouts from the sanitary lateral or replacing a missing or broken lateral clean out cap. More difficult corrections could include cracked sanitary laterals, tree root issues or re-routing drainage. It is impossible to know the extent of these more difficult corrections until a close circuit television of the sanitary sewer lateral is performed. Correcting the deficiencies in a timely manner will be beneficial in maintaining the quality of life and preserving the delicate ecosystem for its inhabitant, the Estuary and the San Francisco Bay.