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Understanding How Smoke Testing Works

Real Estate

The purpose behind smoke testing is to find possible points of infiltration or inflow in a public sanitary sewer system. These areas may result in high flows during a storm or snowmelt events.  Smoke testing is often used for buildings that have a cellar, basement drains, sump pumps, downspout, or yard drains. It can also be used for finding cross-connections between storm drains and sanitary sewers, along with surface water or groundwater intrusion in the sewer.

How Does the Smoke Testing Process Work?

When smoke testing plumbing systems is done, a field crew will blow smoke and air into the sanitary sewer system located in the street. When this is done, the service technicians will monitor where the smoke is escaping from the system. Since the smoke is under pressure, it is going to fill the mainline, along with the connections, and then go down the path of a leak to the ground surface. This is going to show the field crew where the issue is located.


The force required for this testing process is only enough to overcome atmospheric pressure. The smoke should escape via the roof vents on a building.

Benefits of Smoke Testing

This test is an affordable and efficient way to find any areas where unauthorized water is entering into the public part of the sewer system. The smoke that is used is completely harmless and is going to disappear after just a few minutes. With smoke testing done properly, it will also accurately identify any plumbing leaks in a business.

Finding a leak or infiltration in a plumbing system is essential to ensure it continues working properly and efficiently. While this testing process is often used by municipalities, it can also be used by home and business owners who believe there is some type of plumbing leak in their home or building.