Sewer Smoke Testing

Smoke Testing

This summer, field crews will be conducting sanitary sewer smoke testing in selected areas of the District located within the North Sewer Service Area. Pushing non-toxic smoke into the sewer pipes is helpful in detecting connection points where outside surface water can enter into the sewer pipes. During the testing, you may see non-toxic smoke coming from vent stacks on buildings or from holes in the ground. Don’t be alarmed. This simulated “smoke” is safe and non-toxic, has no odor, is non-staining, does not create a fire hazard, and should dissipate quickly. 

What is smoke testing? 
Smoke testing involves pushing a simulated, non-toxic smoke (similar to products used at concerts and theater venues during live performances) through the sewer pipes, then observing and documenting where the smoke exits the system. Field staff set up a blower over a street manhole, and non-toxic smoke is pumped through the sewer line. Under pressure in a confined area, the smoke will fill the main line but then also follow any openings to the surface. The exiting smoke can indicate the location of a broken sewer pipe, manholes, catch basins, or where roof or foundation drains are connected to the sewer system. Ultimately, smoke testing helps identify where inflow is entering the system.SmokeTesting

What is the reason for smoke testing?
Smoke testing is a common method used to locate infiltration and inflow sources in a sewer system that increase capacity in the sewer system. In other words, it is done to locate areas where “clear” water may be entering the sewer system. Typically, direct sources of surface water or groundwater can enter a sewer system during rainfall events – including catch basins, area drains, house roof downspouts, sump pump discharge and/or foundation drains directly connected to the sewer system. Putting non-toxic smoke into the sewers pipes is helpful in detecting direct connection points of groundwater or surface water intrusion into the sewer system. Smoke testing is the fastest and most economical method for identifying breaks within sewer lines.

What are benefits of smoke testing?
Infiltration & Inflow (I&I) reduces pipe capacity and pipe service and can produce future operations and maintenance challenges. Smoke testing is an efficient and low-cost method for avoiding these challenges. Smoke testing provides the information needed to identify and address problem areas before they become deeper issues. Finding and eliminating sources of infiltration and inflow from the sewer system reduces the potential for the backup of sewage into basements and other sewage overflows. Smoke testing can also uncover potential issues in your home that a licensed plumber can further investigate. Sewer gases can be toxic, therefore, fixing any deficiencies in household and business plumbing is strongly recommended.

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