Athens Utilities To Begin Wastewater Collection System Smoke Testing

by Roger Murphy
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ATHENS-Beginning on July 17, residents should not be alarmed if they see smoke rising from the ground, manholes or storm water drains.


The smoke testing is part of a sanitary sewer evaluation study (SSES) to assess the overall current condition of the City of Athens wastewater collection system. Athens Utilities Water Services will perform daily smoke testing on selected wastewater sewer lines from July 2023 through August 2023. It is not necessary for you to be home during the test.


The first areas that will undergo testing, weather permitting, is north of Fifth Avenue and west of Jefferson Street. There is information in both English and Spanish on the website at


Smoke testing is a simple procedure that includes placing a smoke blower over an open manhole and introducing LiquiSmoke through the underground sewer pipes for 3 to 5 minutes. The LiquiSmoke is not a true smoke. It is a mist containing a high percentage of atmospheric moisture. It is not toxic and is harmless to humans, pets, plants, any other living organism and material goods.


Once the LiquiSmoke is placed in the collection system, it can escape through any defects or holes present in the system. The smoke that escapes through system defects can be seen at ground level, and the locations where the smoke is visibly leaking will be identified and tracked. Smoke may exit the ground above leaks in the sewer main, at leaks in the lateral pipe coming from a house or at connections in yards or on buildings.


If a residence has proper plumbing, enough ventilation, and water traps containing water, the smoke should not enter the home. However, if there is a leak in a home’s plumbing or venting system, a broken pipe or an empty water trap, smoke may enter the house. LiquiSmoke that enters a house may cause some light, temporary irritation to nasal passages. Any irritation should disappear quickly after the exposure has stopped. However, it is recommended that unnecessary exposure be avoided for persons who may have a physical condition that could be aggravated by breathing the smoke. If the smoke enters the pipes in a home, it will generally exit through the roof vents and disappear quickly. This is normally the only sign that testing is underway.


The likelihood of the LiquiSmoke entering a building can be decreased by making sure that drain traps are full of water. Fixtures such as sinks, toilets, bathtubs and showers that are used daily will have enough water in their traps. Fixtures that are rarely used may have dry traps that should be filled either by using the fixtures or by filling the drain traps with water before smoke testing begins. If smoke enters an occupied residence, the windows should be opened and any available exhaust fans should be used. The LiquiSmoke will disappear rapidly once fresh air enters.


Study Purpose and Additional Information

The objective of the SSES is to identify locations where infiltration and inflow (I/I) have the potential to occur. Infiltration is groundwater or storm water that enters the sanitary sewer through cracks, holes or open pipe joints. Inflow is storm water that enters the sanitary sewer system directly from a cross-connection with the storm sewer, from storm water collectors such as roof drains or catch basins or from ponding over manholes. I/I can greatly increase the amount of water conveyed by a wastewater collection system. Thus, I/I can decrease the capacity of the collection system and increase the amount of water flowing into the wastewater treatment plant (WWTP). The result is increased treatment costs for the City.


A field crew will be performing the smoke testing to identify areas in the wastewater collection system that may have defects and need improvement. About one week before the testing in your neighborhood, the field crew will distribute door hangers to notify residents of the dates when the smoke tests will occur, as well as information regarding smoke testing. The field crew will be comprised of technicians from Athens Utilities to collect the data needed to develop the City’s comprehensive wastewater program. Once the testing is complete, a cost analysis will be performed to prioritize those areas where repairs are likely to lead to the most effective system improvements for preventing future I/I in the collection system.


The source detection activities of the SSES, such as the smoke testing, are designed to generate data to use in developing recommendations for cost-effective collection system rehabilitation and I/I prevention. Rehabilitation is cost-effective when the repair costs are less than the costs of transporting and treating the I/I. Other activities that the City is undertaking to detect areas that need improvement include the following:

  • Manhole Inspections
  • Dye Water Flooding
  • Flow Monitoring
  • Closed-circuit Television (CCTV) Inspection



Athens Utilities Water Services is developing a comprehensive plan for the City’s wastewater collection system. The Water Services operates and maintains approximately 186 miles of sanitary sewer pipes, 3,721 manholes and 19 pump stations. This system collects and conveys wastewater from customers’ homes to the City’s wastewater treatment plant, which has the capacity to treat an average of 9 million gallons of wastewater per day.


In addition to the SSES, the proposed comprehensive program contains several components. These components are as follows:

  • Mapping the collection system, which includes underground sewer lines
  • Monitoring flows throughout the collection system
  • Developing and maintaining a hydraulic model to evaluate the capacity of the collection system
  • Maintaining a geographical information system (GIS) to track improvements and changes in the collection system over time
  • Maintaining an enterprise asset management system (EAM)
  • Developing a plan to ensure that adequate staffing is available to manage the system
  • Reviewing existing City ordinances and policies and making recommendations to enhance efficient and effective collection system operation


For additional information about the smoke testing program of the City’s comprehensive wastewater collection system program, please contact:

Jimmy Junkin/Athens Utilities Water Services – Director/256-232-1440

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