Smoke Testing

Worker performing a smoke test of Eugene wasterwater line

Smoke testing in 2018.

Sewer Inspection Program

The Public Works Department periodically investigates sanitary sewer lines throughout the city. The inspections help pinpoint defects and improper connections that cause stormwater and groundwater to infiltrate the wastewater collection system. The increase in water can overload the region’s wastewater collection and treatment facility.

Staff test for potential problem areas by utilizing closed circuit television, dyed water and isolated smoke testing.

Smoke Test Safety

Smoke testing is endorsed by the U.S. Environmental Protection Agency. The smoke, called Liquismoke, is non-toxic and does not harm plants or animals. The smoke dissipates quickly and does not leave residues or stains.

Smoke Testing Process

Staff use machinery to blow smoke into the sewer lines. During the tests, a non-toxic white smoke will be released into the public wastewater system. The inspection of where smoke emerges helps crews assess the condition of the system and determine specific problems regarding private building sewer connections as well as public sewer in streets and easements.

smoke rising near a sidewalk


If smoke testing reveals a defect in the public portion of the wastewater collection system, the defect is corrected as soon as possible. If extensive defects are found, capital rehabilitation projects are planned, funded and completed to correct the problem.

Prohibited Connections

If smoke testing identifies a stormwater connection prohibited in the City code, such as a roof drain connected to the sanitary sewer, the property owner is notified and is required to correct the problem.

Private Sewer Defects

If the testing indicates a defect in the private portion of the sewer, which is usually in the line that connects the building to the public sewer, the owner is notified of potential problems with the sewer and repair or replacement of the defective line is recommended.

Important Steps for Homeowners

To minimize the chances of smoke entering your home, we recommend residents pour water into seldom used plumbing fixture drains (such as sinks, laundry tubs, washing machine drains, showers and bathtubs) and any floor drains within the house, basement or garage.


Residents with questions about the City’s smoke testing program can call the Public Works Maintenance Division at 541-682-4800.

Putting water down seldom-used drain minimizes chance of smoke entering home